Histone deacetylase inhibitors

ABSTRACT

The present invention provides histone deacetylase inhibitors of general formula (I), a process for the preparation of such compounds and uses of the compounds in medicine, especially in the treatment of cancers and the inhibition of histone deacetylase activity.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the U.S. National Stage filing of InternationalApplication Serial No. PCT/GB2007/004000 filed Oct. 19, 2007, whichclaims priority to GB Application No. 0620823.5 filed Oct. 19, 2006,each of which is incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present invention relates to histone deacetylase inhibitors, methodsfor the synthesis of such compounds, and use of the compounds inmedicine.

BACKGROUND ART

Histones are the protein component of chromatin. Histones act to formDNA into coils with short lengths of DNA being wrapped around a histonecore so that the DNA is supported by histone octamers to formnucleosomes. These histone proteins have lysine rich tails which whendeacetylated become charged and attracted to the DNA backbone, causingthe DNA to be wrapped around the histone core. This condensing of thechromatin structure means that proteins involved in gene transcriptioncannot gain access to the DNA, resulting in transcriptional repressionor silencing. Histone deacetylase (HDAC) enzymes catalyses thedeacetylation of the lysine tails; the inhibition of these enzymesrapidly leads to the acetylation of the lysine tails of histone, causingthe chromatin to adopt an open conformation, enabling transcription ofgenes, especially genes that influence or maintain a diseased state whensilenced.

A number of recent research reports suggest that chromosometranslocations in cancer cells disrupt proteins involved in the processof histone acetylation and de-acetylation, and that these abnormalproteins cause aberrant gene repression.

It has been proposed that inhibition of histone deacetylase enzymescould relieve such gene repression and reinstate the program ofdifferentiation and apoptosis in a manner analogous to the use ofretinoic acid in the treatment of acute promyelocytic leukemia—a form of“transcription therapy”.

A number of compounds that inhibit HDAC have been described, and severalare in phase I and II clinical trials. These compounds have been shownto induce cell cycle arrest, differentiation and cell death in cancercells growing in vitro and in animal xenograft models.

The most potent HDAC inhibitor, Trichostatin A (TSA) was isolated fromStreptomyces hygroscopicus in the 1970's, as an antifungal antibioticagainst trichophyton. Although potent in vitro, TSA has limitedstability and is therefore not therapeutically useful. Novel compoundswith a similar structure, such as suberoylanilide hydroxamic acid(SAHA):

have activity in pre-clinical models, and have shown anti-canceractivity in clinical. However, this compound is also of limitedstability and is rapidly eliminated, requiring large doses for activity.Other HDAC inhibitors that have been tested in the phase I setting showmajor side effects (e.g. Depsipeptide shows cardiac toxicity), or affecthistone acetylation by an indirect mechanism (CI-994). Others are stillundergoing early clinical investigation.

There is therefore a need for an HDAC inhibitor that is more potent andmetabolically stable than SAHA.

DISCLOSURE OF THE INVENTION

Anew class of compounds that are inhibitors of HDAC has now beenprepared which are believed to be more potent inhibitors of HDAC thansuberoylanilide hydroxamic acid (SAHA) and have enhanced biologicalproperties associated with relief of diseased states, these compoundsare characterised by the presence of a branching moiety, defined by thegroup R³Y═C(ZR²)— in general formula (I).

According to a first aspect of the invention, there is provided acompound of general formula (I): A compound of general formula (I):

in which:

R¹ is (C₆ or C₁₀) aryl (C₆ or C₁₀) arylalkyl, (C₆ or C₁₀) heteroaryl,(C₃-C₈) heterocycloalkenyl, (C₅-C₈) cycloalkene ring, (C₅-C₈)cycloalkyl, (C₅-C₈) heterocycloalkyl or a combination of such rings toform a linked or fused ring system, the cyclic moiety being optionallysubstituted with 1, 2 or 3 substituents, the substituents being selectedfrom (C₁-C₁₀) alkyl, (C₁-C₁₀) alkenyl, (C₁-C₁₀) alkynyl, (C₁-C₁₀)alkoxy, (C₁-C₁₀) thioalkoxy, hydroxyl, hydroxyl, (C₁-C₁₀) hydroxyalkyl,halo, (C₁-C₁₀) haloalkyl, amino, amido, (C₁-C₁₀) alkylamino, (C₁-C₁₀)alkylcarbonyloxy, (C₁-C₁₀) alkoxycarbonyl, (C₁-C₁₀) alkylcarbonyl,(C₁-C₁₀) alkylthiocarbonyl, (C₁-C₁₀) alkylsulfonylamino, aminosulfonyl,(C₁-C₁₀) alkylsulfinyl, or (C₁-C₁₀) alkylsulfonyl, in which any of thesaturated or an unsaturated hydrocarbon chains in the substituents isoptionally interrupted by one or more of O, S, NR, CO, C(N═R), N(R)SO₂,SO₂N(R), N(R)C(O)O, OC(O)N(R), N(R)C(O)N(R), OC(O), C(O)O, OSO₂, SO₂O,or OC(O)O, where R may be independently hydrogen, (C₁-C₆) alkyl, (C₁-C₆)alkenyl, (C₁-C₆) alkynyl, (C₁-C₆) alkoxy, (C₁-C₆) hydroxyalkyl,hydroxyl, (C₁-C₆) halolalkyl, and in which any of the saturated orunsaturated hydrocarbon chains in the substituents may be optionallysubstituted with (C₁-C₆) alkyl, (C₁-C₆) alkenyl, (C₁-C₆) alkynyl,(C₁-C₆) alkoxy, hydroxyl, hydroxyl, (C₁-C₆) hydroxyalkyl, halo, (C₁-C₆)haloalkyl, amino, (C₁-C₆) alkylcarbonyloxy, (C₁-C₆) alkoxycarbonyl,(C₁-C₆) alkylcarbonyl, (C₁-C₆) alkylsulfonylamino, aminosulfonyl, or(C₁-C₆) alkylsulfonyl,

R² and R³ is each independently hydrogen, (C₁-C₆) alkyl, substituted(C₁-C₆) alkyl, or unsaturated (C₂-C₆) alkenyl or alynyl comprising oneor more C═C bond or C≡C bonds, (C₆ or C₁₀) aryl or (C₆ or C₁₀)heteroaryl, or a combination thereof to form a linked or fused ringsystem, (C₁-C₆) alkoxy, (C₁-C₆) thioalkoxy, hydroxyl, (C₁-C₆)hydroxyalkyl, halo, (C₁-C₆) haloalkyl, cyano, nitro, amino, amido,(C₁-C₆) alkylamino, (C₁-C₆) alkylcarbonyloxy, (C₁-C₆) alkoxycarbonyl,(C₁-C₆) alkylcarbonyl, (C₁-C₁₀) alkylthiocarbonyl, (C₁-C₆)alkylsulfonylamino, aminosulfonyl, (C₁-C₆) alkylsulfinyl, or (C₁-C₆)alkylsulfonyl, in which the saturated or an unsaturated hydrocarbonchain is optionally interrupted by O, S, NR, CO, C(N═R), N(R)SO₂,SO₂N(R), N(R)C(O)O, OC(O)N(R), N(R)C(O)N(R), OC(O), C(O)O, OSO₂, SO₂O,or OC(O)O, where R may be independently hydrogen, (C₁-C₆) alkyl, (C₁-C₆)alkenyl, (C₁-C₆) alkynyl, (C₁-C₆) alkoxy, (C₁-C₆) hydroxyalkyl,hydroxyl, (C₁-C₆) halolalkyl, and in which any of the saturated orunsaturated hydrocarbon chains may be optionally substituted with(C₁-C₆) alkyl, (C₂-C₆) alkenyl, (C₂-C₆) alkynyl, (C₁-C₆) alkoxy,hydroxyl, hydroxyl, (C₁-C₆) hydroxylalkyl, halo, (C₁-C₆) haloalkyl,amino, (C₁-C₆) alkylcarbonyloxy, (C₁-C₆) alkoxycarbonyl, (C₁-C₆)alkylcarbonyl, (C₁-C₆) alkylsulfonylamino, aminosulfonyl, or (C₁-C₆)alkylsulfonyl,

R³ is absent when Y stands for O or S,

or R² and R³ may be linked together and such that, together with theintervening atoms, they form a 5, 6 or 7-membered ring containing one ormore heteroatoms, which may be a (C₆ or C₁₀) heteroaryl ring, (C₃-C₈)heterocycloalkenyl ring, or (C₅-C₈) heterocycloalkyl ring, optionallycontaining up to 4 heteroatoms, e.g. oxygen, nitrogen or sulphur, whichring may be fused to further rings as part of a fused ring system, andwhich may bear 1, 2 or 3 substituents, which substituents independentlyhave the same meaning as R² on any or all of those rings,

Q stands for (C₁-C₈) alkyl; C₆ aryl, which may be either unsubstitutedor bear from 1 to 3 substituents each of which independently has thesame meaning as R²; (C₆ aryl)C₁₋₄ alkyl, C₁₋₄alkyl(C₆ aryl) or C₁₋₄alkyl(C₆ aryl)C₁₋₄ alkyl, in which aryl is either unsubstituted or bearsfrom 1 to 3 substituents each of which is independently defined by R²;substituted (C₁-C₈) alkyl where the or each substituent is independentlydefined by R²; or (C₂-C₆) alkenyl or (C₂-C₆) alkynyl comprising one ormore C═C bond or C≡C bond; wherein any saturated or unsaturatedhydrocarbon chain may be optionally interrupted by O, S, NR, CO, C(N═R),where R may be independently hydrogen, (C₁-C₄) alkyl, (C₁-C₄) alkenyl,(C₁-C₄) alkynyl, or (C₁-C₄) alkoxy, and wherein any of the saturated orunsaturated hydrocarbon chains may be optionally substituted with(C₁-C₄) alkyl, (C₂-C₄) alkenyl, (C₂-C₄) alkynyl, (C₁-C₄) alkoxy oramino;

V is OH, SH, SR, OR, NH₂, NHR, NRR, NROH, NHOR, NROR where R mayindependently be hydrogen or (C₁-C₆) alkyl,

Y is oxygen, or sulphur, in which case R³ is absent, or N, in which caseR³ is present and has the meaning defined above; and

Z is O, S, S(═O), S(═O)₂, NR⁴, —N═, CR⁴R⁵, or —C(R⁴)═, where R⁴ and R⁵independently have the same meaning as R²,

All definitions of compounds in the present specification should beunderstood to include tautomeric forms thereof and pharmaceuticallyacceptable salts thereof.

The chain linkage Q (as a whole or in part) may be of any level ofsaturation, and may incorporate rings fused anywhere onto the chainlinked to the —C(═O)V terminus.

In a narrower definition of the groups of the compounds of generalformula (I):

R¹ may be (C₆ or C₁₀) aryl, (C₆ or C₁₀) arylalkyl, (C₆ or C₁₀)heteroaryl, (C₃-C₈) heterocycloalkenyl, (C₅-C₈) cycloalkene ring,(C₅-C₈) cycloalkyl, (C₅-C₈) heterocycloalkyl or a combination thereof toform a linked or fused ring system, the cyclic moiety being optionallysubstituted (1, 2 or 3 substituents) with (C₁-C₆) alkyl, (C₁-C₆)alkenyl, (C₁-C₆) alkoxy, (C₁-C₆) thioalkoxy, hydroxyl, (C₁-C₆)hydroxylalkyl, halo, (C₁-C₆) haloalkyl, amino, amido, (C₁-C₆)alkylamino, (C₁-C₆) alkylcarbonyloxy, (C₁-C₆) alkoxycarbonyl, (C₁-C₆)alkylcarbonyl, (C₁-C₆) alkylsulfonylamino.

Within the above definitions, R¹ may be a benzene ring, that isoptionally substituted with 1, 2 or 3 substituents R⁶, R⁷ and R⁸ (eachof which can be in any location on the ring) each independently standfor (C₁-C₆) alkyl, or where two of the substituents R⁶, R⁷ and R⁸ arelinked to form a five-, six- or seven-membered ring that is fused to thebenzene ring and that is heteroaryl, heterocycloalkenyl, cycloalkenyl,cycloalkyl or heterocycloalkyl.

R² and R³ may each independently be hydrogen, (C₁-C₄) alkyl, substituted(C₁-C₄) alkyl, or unsaturated (C₁-C₄) comprising one or more C═C bond orC≡C bond, (C₆ or C₁₀) aryl or (C₆ or C₁₀) heteroaryl, or a combinationthereof to form a linked or fused ring system, or (C₁-C₄) alkyl, (C₁-C₄)alkenyl, (C₁-C₄) alkynyl, (C₁-C₄) alkoxy, hydroxyl, (C₁-C₄)hydroxyalkyl, halo, (C₁-C₄) haloalkyl, amino, amido, (C₁-C₄) alkylamino,(C₁-C₄) alkylcarbonyloxy, (C₁-C₄) alkoxycarbonyl, (C₁-C₄) alkylcarbonyl,(C₁-C₄) alkylsulfonylamino, in which the saturated or an unsaturatedhydrocarbon chain is optionally interrupted by O, S, NR, CO, C(NR),N(R)SO₂, SO₂N(R), N(R)C(O)O, OC(O)N(R), N(R)C(O)N(R), OC(O), C(O)O,OSO₂, or SO₂O, where R may be independently hydrogen, (C₁-C₄) alkyl,(C₁-C₄) alkenyl, (C₁-C₄) alkynyl, (C₁-C₄) alkoxy, (C₁-C₄) hydroxyalkyl,hydroxyl, (C₁-C₄) halolalkyl, where each of the saturated or unsaturatedhydrocarbon chains may be optionally substituted with (C₁-C₄) alkyl,(C₁-C₄) alkenyl, (C₁-C₄) alkynyl, (C₁-C₄) alkoxy, hydroxyl, (C₁-C₄)hydroxyalkyl, halo, (C₁-C₄) haloalkyl, amino, (C₁-C₄) alkylcarbonyloxy,(C₁-C₄) alkoxycarbonyl, (C₁-C₄) alkylcarbonyl, (C₁-C₄)alkylsulfonylamino,

Alternatively, R² and R³ may be such that, together with the interveningatoms, they form a 5, 6 or 7-membered ring containing one or moreheteroatoms, which may be a (C₆ or C₁₀) heteroaryl ring, (C₃-C₈)heterocycloalkenyl ring, or (C₅-C₈) heterocycloalkyl ring, optionallycontaining up to 4 heteroatoms, e.g. oxygen, nitrogen, sulphur orphosphorus, which ring may be fused to further rings as part of a fusedring system, and which may bear 1, 2 or 3 substituents, whichsubstituents independently have the same meaning as R² on any or all ofthose rings, wherein R⁴ and R⁵ each independently has the same meaningas R²;

In a narrower definition, R² and R³ are linked and together with theintervening atoms to form an optionally substituted 5 or 6 memberedheterocyclic ring containing 1, 2 or 3 heteroatoms; alternatively R³ isabsent and R² stands for a benzene ring that is optionally substitutedwith 1, 2 or 3 substituents R⁶, R⁷ and R⁸ (each of which can be in anylocation on the ring) each independently stands for (C₁-C₆) alkyl, orwhere two of the substituents R⁶, R⁷ and R⁸ are linked to form a five-,six- or seven-membered ring that is fused to the benzene ring and thatis heteroaryl, heterocycloalkenyl, cycloalkenyl, cycloalkyl orheterocycloalkyl.

Q may stand for (C₁-C₈) alkyl; C₆ aryl, which may be eitherunsubstituted or bear from 1 to 3 substituents each of which isindependently defined by R²; (C₆ aryl)C₁₋₄ alkyl, C₁₋₄ alkyl(C₆ aryl) orC₁₋₄ alkyl(C₆ aryl)C₁₋₄ alkyl, in which aryl is either unsubstituted orbears from 1 to 3 substituents each of which is independently defined byR²; substituted (C₁-C₈) alkyl where the or each substituent isindependently defined by R²; or (C₂-C₆) alkenyl or (C₂-C₆) alkynylcomprising one C═C bond or C≡C bond; wherein any saturated orunsaturated hydrocarbon chain may be optionally interrupted by O, S, NR,CO, where R may be independently hydrogen, (C₁-C₄) alkyl, (C₁-C₄)alkenyl, (C₁-C₄) alkynyl, or (C₁-C₄) alkoxy, and wherein any of thesaturated or unsaturated hydrocarbon chains may be optionallysubstituted with (C₁-C₄) alkyl, (C₂-C₄) alkenyl, (C₂-C₄) alkynyl,(C₁-C₄) alkoxy or amino.

In a narrower definition, Q stands for (C₁-C₈) alkyl; C₆ aryl, (C₆aryl)C₁₋₄ alkyl, C₁₋₄ alkyl(C₆ aryl) or C₁₋₄ alkyl(C₆ aryl) or C₁₋₄alkyl, wherein any aryl ring may be either unsubstituted or bear from 1to 3 substituents each of which is independently defined by R²; andwherein each alkyl group may optionally contain one or more substituentseach of which has the same meaning as R²; (C₁-C₄) alkyl, (C₂-C₄)alkenyl, (C₂-C₄) alkynyl, (C₁-C₄) alkoxy or amino; in a still narrowerdefinition, Q stands for C₁₋₁₀ alkyl, e.g. C₁₋₁₀ alkyl such asC₃₋₆alkyl, that optionally includes a single double bond and isoptionally interrupted by a C₆ aryl ring, e.g. a benzene ring.

V may be OH, OMe, OEt, NH₂, NHR, NRR, NHOH, where R is H, Me or Et, andtypically V is NHOH, NHOMe or NHOEt, most notably NHOH.

Y is oxygen or sulfur or nitrogen, typically oxygen or nitrogen; and

Z is O, S, S(═O), S(═O)₂, NR⁴, —N═, CR⁴R⁵ or —C(R⁴)═, where R⁴ and R⁵may each independently have the same meaning as R², typically NH, —CH═or S.

In a further embodiment of the present invention, R² and R³ are linkedto form with the intervening atoms a 5-, 6- or 7-membered ring, whichmay be partly saturated or aromatic. In the ring, at least one (andoptionally both) of the atoms Y and Z stands for a hetero atom (N, O orS) or a group containing a hetero atom (S(═O), S(═O)₂, NR⁴). The ringmay be part of a fused ring system and the ring or fused ring system maybe substituted by a group having the meaning R².

The present invention also provides a group of compounds within thegeneral formula (I) having the formula (Ia)

where R¹, R², R³ and Q have the definitions given above for formula (I).

In one group of compounds according to the general Formula I and Ia, R²and R³ are linked by two atoms W—X where W and X are independently O, S,S(═O), S(═O)₂, NR⁴, —N═, CR⁴R⁵, or —C(R⁴)═, where R⁴ and R⁵ eachindependently has the same meaning as R²; the linkage between W and X,and between X and Z are either both single bonds, or one single bond andone double bond Q is as defined above. In this case, V is —OH, —OC₂H₅,—OCH₃, or —NHOH.

Such compounds may be defined by formula (A)

in which:

W, X and Z are independently O, S, S(═O), S(═O)₂, NR⁴, —N═, CR⁴R⁵, or—C(R⁴)═, where R⁴ and R⁵ may independently have the same meaning as R²;alternatively W and X together or X and Z together may form a 5 or 6membered fused ring, e.g. a fused benzene ring, that optionally includesone or more heteroatoms and that optionally carry one or moresubstituents have the same meaning as R²

the bonds between W and X, and between X and Z may be either both singlebonds, or one single bond and one double bond,

R⁶, R⁷ and R⁸ (each of which can be in any location on the ring) eachindependently has the same meaning as R², or where two of thesubstituents R⁶, R⁷ and R⁸ are linked to form a five-, six- orseven-membered ring that is fused to the benzene ring and that isheteroaryl, heterocycloalkenyl, cycloalkenyl, cycloalkyl orheterocycloalkyl and is either unsubstituted or bears one, two or threesubstituents that each independently has the same meaning as R²,

and Q is as defined above.

Typical compounds on this type are those in which:

W, X and Z are each independently O, S, NR⁴, —N═, CR⁴R⁵ or —C(R⁴)═,where R⁴ and R⁵ may independently have the same meaning as R²,

and where the linkage between W and X, and between X and Z may be eitherboth single bonds, or one single bond and one double bond,

where R⁸ stands for H and preferably R⁷ stands for H and R⁶ is an atomor group within the definition of R² having 6 atoms or fewer,

and Q is as defined above.

Especially noteworthy for compounds of type (A) are when Z stands for O,S, NR⁴, CR⁴R⁵, or —C(R⁴)═, where R⁴ and R⁵ may be independently R², andwhere W and X are linked by a double bond and comprise either bothcarbon atoms (CR⁴R⁵ and —C(R⁴)═) or one carbon atom and a nitrogen atom(NR⁴ and —C(R⁴)═).

A further group of compounds within the general formulae (I) and (Ia)have the formula (Ib)

where R¹ and R³ to R⁵ have the definitions given above for formula (I).

In another embodiment, in the compounds of the general formula I R² andR³ are linked in the form of the atoms or groups W—X—Y in which W, X,and Y and Z may independently be O, S, S(═O), S(═O)₂, NR⁴, —N═, CR⁴R⁵,or —C(R⁴)═, where R⁴ and R⁵ may each independently have the same meaningas R²; or Y may represent a bond linking X and Z,

and where the linkage between the pairs of atoms WX, XY and YZ may allbe single bonds, or W—X and X—Y may be single bonds and Y=Z a doublebond, or X—Y and Y—Z may be single and W═X a double bond, oralternatively X═Y may be a double bond, or lastly both W═X and Y=Z maybe double bonds;

alternatively W and X together or X and Y together may form a 5 or 6membered fused ring, e.g. a fused benzene ring, that optionally includesone or more heteroatoms and that optionally carry one or moresubstituents have the same meaning as R² and Q is as defined above, e.g.an optionally substituted C₃-C₅ alkylene chain containing one or moreunsaturated bonds;

in this case V may be —OH, —OC₂H₅, —OCH₃, or —NHOH.

In a still further group of compounds within the general Formula (I) arethose defined by formula (B)

where W, X, Y and Z may independently be O, S, S(═O), S(═O)₂, NR⁴, —N═,CR⁴R⁵, or —C(R⁴)═, where R⁴ and R⁵ may be independently R², where R⁴ andR⁵ may be independently R², or W and X together or X and Y together mayform a 5 or 6 membered fused ring, e.g. a fused benzene ring, thatoptionally includes one or more heteroatoms and that optionally carryone or more substituents have the same meaning as R² or Y may representa bond linking X and Z;

and where the linkage between the pairs of atoms WX, XY and YZ

(a) are all be single bonds, or

(b) one of the linkages WX, X—Y YZ is a double bond and the otherlinkages are single bonds,

(c) both WX and YZ are double bonds and XY is a single bond or

(d) WX is a single or double bond and Y is a bond linking X and Z, Ybeing a single bond if WX is a double bond or a single or double bond ifWX is a single bond.

R⁶, R⁷ and R⁸ (each of which may have any location on the ring) mayindependently each have the same meaning as R², or two of thesubstituents R⁶, R⁷ and R⁸ may be linked to form a five-, six- orseven-membered ring that is fused to the benzene ring and that isheteroaryl, heterocycloalkenyl, cycloalkenyl, cycloalkyl orheterocycloalkyl either unsubstituted or bearing one, two or threesubstituents that each independently has the same meaning as R²,

and where Q is as defined above.

A narrower group of compounds according to the general formula (B) arethose where W, X, Y and Z are each independently be O, S, NR⁴, —N═,CR⁴R⁵, or —C(R⁴)═, where:

R⁴ and R⁵ may each independently have the same meaning as R², or Y is abond between X and Z;

the linkage between the pairs of atoms WX, XY and YZ may all be singlebonds, or W—X and X—Y may be single bonds and Y=Z a double bond, or X—Yand Y—Z may be single and W═X a double bond, or alternatively X═Y may bea double bond, or lastly both W═X and Y=Z may be double bonds,

R⁸ stands for H and R⁷ stands for H and R⁶ is an atom or group withinthe definition of R² and having 6 atoms or fewer,

and where Q as defined above.

Especially noteworthy for type (B) are those:

where Z stands for —N═ or —C(R⁴)═, where R⁴ has the same meaning as R²as described immediately above,

where a double bond links both W═X and Y=Z, and where W, X and Y are anycombinations of, NR⁴, —N═, C(R⁴)(R⁵), or —C(R⁴)═, where substituents R⁴and R⁵ are as defined above.

Another group of compounds within the general formula (I) and (Ia) arethose in which Y stands for O, R³ is absent, Z stands for NH and R¹ andR² are identical 15. In this case V may be —OH, —OC₂H₅, —OCH₃, or —NHOH.

Among such compounds are those having the formula (Ic)

where both R¹ groups are identical and R¹ and Q has the meanings givenabove for formula (I).

In a still further embodiment the compounds may be defined by formula(C)

where R⁶, R⁷ and R⁸ (each of which may have any location on the ring)each independently has the same meaning as R², or two of thesubstituents R⁶, R⁷ and R⁸ may be linked to form a five-, six- orseven-membered ring that is fused with the benzene ring and that isheteroaryl, heterocycloalkenyl, cycloalkenyl, cycloalkyl orheterocycloalkyl either unsubstituted or bearing one, two or threesubstituents that each independently has the same meaning as R², and

Q is as defined above.

Where R¹ stands for a phenyl ring substituted by substituents R⁶, R⁷ andR⁸, R⁸ and R⁷ may stand for H and R⁶ may stand for an atom or groupwithin the definition of R² having 6 atoms or fewer.

Compounds in which R² and R³ are linked to form a ring (especiallycompounds of the general formulae A and B are preferred over compoundsof the general formula C since they are more soluble and tend to have agreater metabolic stability.

DEFINITIONS

In this specification the term “compound” includes “salt” or “hydrate”unless the context requires otherwise.

As used herein the term “halogen” or its abbreviation “halo” meansfluoro, chloro, bromo or iodo.

As used herein the term “hetero” refers to the presence of one or moreatoms that are not carbon atoms. Suitable heteroatoms include, oxygen,sulphur, nitrogen or phosphorus, represented as O, S and N,respectively.

As used herein the term “(C₁-C₆) alkyl” refers to straight chain orbranched chain hydrocarbon groups having from one to six carbon atoms.Illustrative of such alkyl groups are methyl, ethyl, propyl, isopropyl,butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, and hexyl.From one to five carbon atoms (C₁-C₅), or from one to four carbon atoms(C₁-C₄) may be preferred.

As used herein the term “(C₁-C₁₂) alkyl” refers to straight chain orbranched chain hydrocarbon groups having from one to ten carbon atoms.Illustrative of such alkyl groups are methyl, ethyl, propyl, isopropyl,butyl, isobutyl, sec-butyl, tert-butyl, pentyl, neopentyl, hexyl,heptyl, octyl, nonyl, decyl, undecyl and dodecyl. From one to ten carbon(C₁-C₁₀) atoms or from one to six carbon atoms (C₁-C₆) may be preferred.

The term “(C₆ or C₁₀) aryl” includes phenyl and naphthyl, eitherunsubstituted or bearing one two or three substituents of the type R².

As used herein, the term “(C₅-C₈)cycloalkyl” refers to an alicyclicgroup having from 5 to 8 carbon atoms, either unsubstituted or bearingone two or three substituents of the type R². Illustrative of suchcycloalkyl groups are cyclopentyl and cyclohexyl.

As used herein, the term “(C₅-C₈)cycloalkene ring” refers to analicyclic ring having from 5 to 8 atoms and having in addition one ormore double bonds, the ring being either unsubstituted or bearing onetwo or three substituents of the type R². Illustrative of suchcycloalkenyl groups are cyclopentenyl, cyclohexenyl, cycloheptenyl andcyclooctenyl.

In compounds of this invention, the presence of an asymmetric carbonatom gives rise to enantiomers. The presence of several asymmetriccarbon atoms give rise to diastereoisomers, each of which consists oftwo enantiomers, with the appropriate R or S stereochemistry at eachchiral centre. The invention is understood to include all suchdiastereoisomers, optically active enantiomers and mixtures thereof.

The term “suitable salt” refers to a salt prepared by contacting acompound of formula (I) with an acid or base whose counterpart ion doesnot interfere with the intended use of the compound. Examples includethe sodium salt or magnesium salt of a phosphate derivative or the saltformed from a primary, secondary or tertiary amine where the compound ofgeneral formula (I) is a carboxylic acid. An example of a primary aminesalt can be the cyclohexylammonium salt, a suitable secondary amine saltmay be the piperidine salt and a tertiary amine salt may be thetriethylamine salt.

References to alkylamino include mono-, di-, or tri-substituted carbonatoms unless the context specifies otherwise. References to amidoinclude CONR, where R may be hydrogen.

References to a fused ring system include both aromatic and alicyclicring systems. The ring may be fully or partially saturated orunsaturated, and may be either unsubstituted or bearing one two or threesubstituents of the type R².

Unless the context specifies otherwise, substitutions to benzene rings(C₆ aryl) may be at the ortho-, meta- or para-positions.

As used herein, the term “(C₆-C₁₀) heteroaryl” refers to a 6 or10-membered ring system having one or more heteroatoms in the ring whichmay be either unsubstituted or bearing one two or three substituents ofthe type R².

As used herein, the term “(C₃-C₈) heterocycloalkenyl” refers to a ringsystem having from 3 to 8 members, preferably 5, 6 or 7 members, inwhich one or more heteroatoms is present in the ring, which may beeither unsubstituted or bearing one two or three substituents of thetype R².

As used herein, the term “(C₅-C₈) heterocycloalkyl” refers to a ringsystem having from 5 to 8 members, preferably 5, 6 or 7 members, inwhich one or more heteroatoms is present in the ring, which may beeither unsubstituted or bearing one two or three substituents of thetype R².

The expression used herein that a group or atom A “has the same meaningas” another group or atom B (and similar expressions) is intended tomean that A may have any of the meanings defined elsewhere for B and theexpression is not intended to be limited to require that, in a givencompound, A and B must be identical.

All tautomers (especially involving some atoms of W, X Y and Z) areincluded. Tautomers arise by relocation of a hydrogen atom from oneheteroatom to another heteroatom with concomitant migration of at leastone double bond.

Compounds falling within the scope of general formula (I) include thosein which R¹ is a benzene ring, either substituted or preferablyunsubstituted, and where Q may be C₃₋₆ alkyl.

Other compounds falling within the scope of general formula (I) arethose in which R¹ is a benzene ring, either substituted or preferablyunsubstituted, and where either:

-   -   Y═O (R³ absent) with Z═NH and R² is a benzene ring, either        substituted or preferably unsubstituted,    -   or where R² and R³ together with the intervening atoms form a        five-membered heteroaromatic ring or a six-membered        heteroaromatic ring containing from 1-3 nitrogen atoms and 0-2        sulfur atoms and 0-2 oxygen atoms, and where there are 0-2        substituents on that heteroaromatic ring.

Examples of such compounds are compounds A1, B1 and C1.

Other compounds of general formula (I) include those in which,independently or in any compatible combination:

Ethyl 7-(3-methyl-1,2,4-thiadiazol-5-yl)-7-phenylcarbamoylheptanoate(5a)

2-(3-Methyl-1,2,4-thiadiazol-5-yl)octanedioic acid 8-hydroxyamide1-phenylamide (A1)

Ethyl 7-phenylcarbamoyl-7-pyrazin-2-ylheptanoate (10a)

2-(Pyrazin-2-yl)octanedioic acid 8-hydroxyamide 1-phenylamide (B1)

7,7-Bis-phenylcarbamoyl-heptanoic acid ethyl ester (16a)

7,7-Bis-phenylcarbamoyl-heptanoic acid (16b)

2-Phenylcarbamoyl-octanedioic acid 8-hydroxyamide 1-phenylamide (C1, orUCL67022)

According to a second aspect of the invention there is provided aprocess for the preparation of a compound of general formula (I), as setout in Scheme 1

in which the groups:

R¹-R⁸ and V are as previously specified.

R⁹ is preferably tert-butyl but may be any group that can be hydrolysedunder neutral or acidic conditions without the hydrolysis of R¹¹.

R¹⁰ is H (which may be used in the manufacture of compounds (C) e.g.according to Scheme 4 set out below) and otherwise R¹⁰ stands forR³Y═CZR²; more specifically, for compounds (A) R¹⁰ stands for R³═NZR²and for compounds (B) R¹⁰═R³N═CC R² R⁴ R⁵.

OR¹¹ is any group displaceable by hydroxylamine, but not displaceable byR¹NH₂ (where R¹ is the group used in the molecule concerned, which fallswithin the definition above), and can be aryl, heteroaryl or (C₁-C₆)alkyl, preferably methyl or ethyl.

R¹² stands for COOH for compounds (C) and otherwise R¹²═R³Y═CZR²; morespecifically, for compounds (A) R¹²═R³N═CZR² and for compounds (B)R¹²═R³N═CC R²R⁴R⁵.

T is a leaving group that may be a halogen atom (e.g. bromine, chlorine,iodine), or benzenesulphonate, para-toluenesulphonate,trifluoromethylsulphonate but which is preferably bromo for compound(III).

The process comprises the addition of a compound of general formula (II)to one of general formula (III) in the presence of a base such as analkali metal alkoxide or an alkali metal, or preferably an alkali metalhydride, especially sodium hydride, to give compound (IV), followed byhydrolysis, or hydrolysis and decarboxylation, to give (V) where and R⁹is RY=CZR² or COOH, It is often convenient to prepare compound (II) byaddition of a malonic ester to R³Y═C(T)ZR² where T is preferablyhalogen, especially bromo- or chloro-.

Hydrolysis of compound (IV) may be suitably carried out under acidicconditions, for example with aqueous mineral acid of aromatic sulphonicacids. Decarboxylation may be carried out by heating, with our withoutacid. Where group R¹⁰ stands for H, this hydrolysis can convert the Hinto a carboxylic acid group, which may be used in the scheme formanufacturing compounds C.

An embodiment of the process of this aspect of the invention maycomprise the addition of a compound of general formula (3) to generalformula (4), in the presence of a base such as an alkali metal alkoxideor an alkali metal, or preferably an alkali metal hydride, especiallysodium hydride, followed by hydrolysis, or hydrolysis anddecarboxylation.

Another embodiment of the process of this aspect of the invention maycomprise the addition of a compound of general formula (10) to acompound of general formula (4), in the presence of a base such as analkali metal alkoxide or an alkali metal, or preferably an alkali metalhydride, especially sodium hydride, followed by hydrolysis, orhydrolysis and decarboxylation.

Another embodiment of the process of this aspect of the invention formaking the compound of general formula (IV) in which R¹⁰ stands for H(especially for the production of compounds of the formula C accordingto reaction scheme 4 below) may also comprise the addition of a compoundof di-tert-butyl malonate to a compound of general formula (4) in thepresence of a base such as an alkali metal alkoxide or an alkali metal,or preferably an alkali metal hydride, especially sodium hydride,followed by hydrolysis, or hydrolysis and decarboxylation.

Reaction scheme 1 further involves reacting the carboxylic acid compound(V) with an amine in the presence of a coupling agent to give amidocompounds (VI).

An embodiment of the process of this aspect of the invention maycomprise the addition of a compound of general formula (6) to generalformula (7), in the presence of a coupling agent, especially oxalylchloride or thionyl chloride (added to 6 to form the acid chloridefollowed by addition of 7), but also other commonly used coupling agentsfor amide formation including EDCI in the presence of HOBt,dicyclohexylcarbodiimide (DCC).

A embodiment of the process of this aspect of the invention may comprisethe addition of a compound of general formula (12) to general formula(7), in the presence of a coupling agent, especially oxalyl chloride orthionyl chloride (added to 12 to form the acid chloride followed byaddition of 7), but also other commonly used coupling agents for amideformation including EDCI in the presence of HOBt,dicyclohexylcarbodiimide (DCC).

Another embodiment of the process of this aspect of the invention maycomprise the addition of a compound of general formula (15) to generalformula (7), in the presence of a coupling agent, especially oxalylchloride or thionyl chloride (added to 15 to form the acid chloridefollowed by addition of 7), but also other commonly used coupling agentsfor amide formation including EDCI in the presence of HOBt,dicyclohexylcarbodiimide (DCC).

According to a third aspect of the invention, there is provided aprocess for the preparation of a compound of general formula (I), byreaction of compounds (VI) with hydroxylamine or a derivative ofhydroxylamine, or an otherwise substituted version of hydroxylamine, inthe presence or absence of a base or alkali, especially potassiumhydroxide.

A embodiment of the process of this aspect of the invention is theconversion of esters 8.1 into compounds (A).

A embodiment of the process of this aspect of the invention is theconversion of esters 13.1 into compounds (B).

Another embodiment of the process of this aspect of the invention is theconversion of esters 16.1 into compounds (C).

In the above ester conversions, Q, W, X, Y, Z and R⁶ to R⁸ are asdefined above.

Reference in the present application is now made to a number of reactionschemes which are present for the purposes or illustration only and arenot to be construed as being limiting on the present invention.

Synthetic Routes.

In Scheme 2 is shown a general route to hydroxamic acid derivatives (A)that contain a heterocyclic ring linked to form a branch point.Compounds (A) can be accessed through a sequence involving addition ofthe anion of a malonic ester, preferably di-tert-butyl malonate, to afive-membered heterocycle 2 that contains a displaceable group (T) suchas Cl or Br to give the malonate 3 which is then deprotonated with abase, preferably NaH in tetrahydrofuran, but also an alkalitert-butoxide such as KOBu^(t) followed by alkylation with an α,ω-bromoester such as 4 to give the triester 5. Hydrolysis of 5 can be performedunder a variety of standard conditions which if mild, such as gentleheating with dilute mineral acid, or other acid catalyst such as p-TsOHafford the corresponding diacid. Hydrolysis of 5 can also be performedusing alkaline hydrolysis followed by acidification to give thecorresponding diacid. However, treatment of 5 with more concentratedmineral acid (of varying strengths but preferably an aqueous solution)or other acid catalysts such as p-TsOH, or appreciable heating of 5alone generally results in the monoacid 6 which can be condensed with avariety of amines, but preferably an aniline 7, using a variety ofreagents including thionyl chloride or oxalyl chloride on the acid togenerate the acid chloride which is reacted with the aniline 7 in thepresence of a base such as triethylamine, pyridine or perhaps alkalimetal hydroxides such as NaOH or KOH in water, if necessary in thepresence also of an organic solvent (i.e. Schotten-Baumann typeconditions) to give the anilide 8. However, especially useful is1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI) inthe presence (or sometimes the absence) of 1-hydroxybenzotriazole (HOBt)for the formation of anilides 8. Reaction of 8 with hydroxylamine(usually an aqueous solution, but otherwise a salt such as hydroxylaminehydrochloride together with a base, typically sodium hydroxide orpotassium hydroxide, affords the hydroxamic acid (A).

Although a sequence of general utility is implied in Scheme 2, compoundsof particular interest include R⁶═R⁷═R⁸═H and Z═N or CR⁴, where R⁴ is asdefined above; Compound A1 (above) is representative of these compounds.

Scheme 2 is intended to include aromatic and heteroaromatic rings,single, fused or poly-condensed ring systems without limitation (inplace of the single benzene ring shown for compounds 8 and (A)) and withor without a wide variety of substituents. As an example, thiadiazole 2awas shown to react with bromo ester 4a to give triester 13 which wasreacted with aqueous hydroxylamine to give hydroxamic acid 5a which washydrolysed and decarboxylated to give monoacid 6a which was condensedwith aniline to give 7a which was converted by hydroxylamine into (A1).Hydroxamic acids of type (A) are of particular interest as inhibitors ofhistone deacetylase. Some of the carboxylic acids corresponding to (A)are also inhibitors of histone deacetylase.

In Scheme 3 is shown a general route to hydroxamic acid derivatives (B)that contain a heterocyclic ring linked to the branch point. Compounds(B) can be accessed through a sequence involving addition of the anionof a malonic ester, preferably di-tert-butyl malonate, to a six-memberedheterocycle 9 that contains a displaceable group (T) such as Cl or Br togive the malonate 10 which is then deprotonated with a base, preferablyNaH in tetrahydrofuran, but also an alkali tert-butoxide such asKOBu^(t) followed by alkylation with an α,ω-bromo ester such as 4 togive the triester 11. Hydrolysis of 11 can be performed under a varietyof standard conditions which if mild, such as gentle heating with dilutemineral acid, or other acid catalyst such as p-TsOH afford thecorresponding diacid. Hydrolysis of 11 can also be performed usingalkaline hydrolysis followed by acidification to give the correspondingdiacid. However, treatment of 11 with more concentrated mineral acid (ofvarying strengths but preferably an aqueous solution) or other acidcatalysts such as p-TsOH, or appreciable heating of 11 alone generallyresults in the monoacid 12 which can be condensed with a variety ofamines, but preferably an aniline 7, using a variety of reagentsincluding thionyl chloride or oxalyl chloride on the acid to generatethe acid chloride which is reacted with the aniline 7 in the presence ofa base such as triethylamine, pyridine or perhaps alkali metalhydroxides such as NaOH or KOH in water, if necessary in the presencealso of an organic solvent (i.e. Schotten-Baumann type conditions) togive the anilide 13. However, especially useful is1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDCI) inthe presence or sometimes the absence of 1-hydroxybenzotriazole (HOBt)for the formation of anilides 13. Reaction of 13 with hydroxylamine(usually an aqueous solution, but otherwise a salt such as hydroxylaminehydrochloride together with a base, typically sodium hydroxide orpotassium hydroxide) affords the hydroxamic acid (B).

Although a sequence of general utility is implied in Scheme 3, compoundsof particular interest include R⁶═R⁷═R⁸═H and Z═N or CR⁴, where R⁴ is asdefined above; Compound B1 (above) is representative of these compounds

Scheme 3 is intended to include aromatic and heteroaromatic rings,single, fused or poly-condensed ring systems without limitation (inplace of the single benzene ring shown for compounds 13 and (B)) andwith or without a wide variety of substituents. As an example, pyrazine9a was shown to react with di-tert-butyl malonate to give triester 10awhich was reacted with ester 4a to give 11a which was hydrolysed anddecarboxylated to give monoacid 12a which was condensed with aniline togive 13a which was converted by hydroxylamine into (B1). Hydroxamicacids of type (B) are of particular interest as inhibitors of histonedeacetylase. Some of the carboxylic acids corresponding to (B) are alsoinhibitors of histone deacetylase.

An optional feature of Schemes 2 and 3 is the possibility of couplingthe malonic ester with 2 or 9, under catalysis by palladium in ligatedform. Representative is the reaction of 2 or 9 where T=I but preferablyT=Br in the presence of a phosphane such as (t-Bu)₃P, a base such ast-BuOK or NaH, and a catalytic amount of bis(dibenzylideneacetone)palladium. Alternatively, a system of Ph₃P, a base such as t-BuONa and acatalytic amount of palladium(II) acetate may be appropriate. In anotheralternative, usually less preferable, such reactions may be achieved inthe presence of a base such as sodium hydride, copper (I) bromide andhexamethylphosphoramide. In many cases, a reaction temperature between0-100° C. may be used.

In Scheme 4 is shown a general route to hydroxamic acid derivatives (C)that contain two carboxamides linked to form a branch point. Compounds(C) can be accessed through a sequence involving addition of the anionof a malonic ester, preferably di-tert-butyl malonate, generated using abase, preferably NaH in tetrahydrofuran, but also an alkalitert-butoxide such as KOBu^(t) followed by alkylation with an ester suchas 4 (preferably with T=Br) to give the triester 14. Hydrolysis of 14can be performed under a variety of standard conditions which if mild,such as gentle heating with dilute mineral acid, or other acid catalystsuch as p-TsOH afford the diacid. The diacid 15 can be condensed with avariety of amines, but preferably an aniline 7, using a variety ofreagents including thionyl chloride or oxalyl chloride on the acid togenerate the acid chloride which is reacted with the aniline 7 in thepresence of a base such as triethylamine, pyridine or perhaps alkalimetal hydroxides such as NaOH or KOH in water, if necessary in thepresence also of an organic solvent (i.e. Schotten-Baumann typeconditions) to give the anilide 16. However, especially useful is oxalylchloride for the formation of anilides 16. Reaction of 16 withhydroxylamine (usually an aqueous solution, but otherwise a salt such ashydroxylamine hydrochloride together with a base, typically sodiumhydroxide or potassium hydroxide) affords the hydroxamic acid (C).

Although a sequence of general utility is implied in Scheme 4, compoundsof particular interest include R⁶═R⁷=R⁸═H and n=1-3, where R⁴ is asdefined above; Compound C1 (above) is representative of these compounds.

Scheme 4 is intended to include aromatic and heteroaromatic rings,single, fused or poly-condensed ring systems without limitation (inplace of the single benzene ring shown for compounds 16 and (C)) andwith or without a wide variety of substituents. As an example,di-tert-butyl malonate was shown to react with ester 4a to give triester14a which was hydrolysed with mineral acid to give 15a which wasconerted into its di-acid chloride. The crude acid chloride wascondensed with aniline to give 16a which was converted by hydroxylamineinto (C1). Hydroxamic acids of type (C) are of particular interest asinhibitors of histone deacetylase. Some of the carboxylic acidscorresponding to (C) are also inhibitors of histone deacetylase.

According to a fourth aspect of the invention, there is provided apharmaceutical composition comprising a compound of general formula (I),and optionally a pharmaceutically acceptable adjuvant and/or diluent.

The medicament will usually be supplied as part of a sterile,pharmaceutical composition which will normally include apharmaceutically acceptable carrier. This pharmaceutical composition maybe in any suitable form, (depending upon the desired method ofadministering it to a patient).

It may be provided in unit dosage form, will generally be provided in asealed container and may be provided as part of a kit. Such a kit wouldnormally (although not necessarily) include instructions for use. It mayinclude a plurality of said unit dosage forms.

The pharmaceutical composition may be adapted for administration by anyappropriate route, for example by the oral (including buccal orsublingual), rectal, nasal, topical (including buccal, sublingual ortransdermal), vaginal or parenteral (including subcutaneous,intramuscular, intravenous or intradermal) route. Such compositions maybe prepared by any method known in the art of pharmacy, for example byadmixing the active ingredient with the carrier(s) or excipient(s) understerile conditions.

Pharmaceutical compositions adapted for oral administration may bepresented as discrete units such as capsules or tablets; as powders orgranules; as solutions, syrups or suspensions (in aqueous or non-aqueousliquids; or as edible foams or whips; or as emulsions)

Suitable excipients for tablets or hard gelatine capsules includelactose, maize starch or derivatives thereof, stearic acid or saltsthereof. Suitable excipients for use with soft gelatine capsules includefor example vegetable oils, waxes, fats, semi-solid, or liquid polyolsetc. For the preparation of solutions and syrups, excipients which maybe used include for example water, polyols and sugars. For thepreparation of suspensions oils (e.g. vegetable oils) may be used toprovide oil-in-water or water in oil suspensions.

Pharmaceutical compositions adapted for transdermal administration maybe presented as discrete patches intended to remain in intimate contactwith the epidermis of the recipient for a prolonged period of time. Forexample, the active ingredient may be delivered from the patch byiontophoresis as generally described in Pharmaceutical Research,3(6):318 (1986).

Pharmaceutical compositions adapted for topical administration may beformulated as ointments, creams, suspensions, lotions, powders,solutions, pastes, gels, sprays, aerosols or oils. For infections of theeye or other external tissues, for example mouth and skin, thecompositions are preferably applied as a topical ointment or cream. Whenformulated in an ointment, the active ingredient may be employed witheither a paraffinic or a water-miscible ointment base. Alternatively,the active ingredient may be formulated in a cream with an oil-in-watercream base or a water-in-oil base. Pharmaceutical compositions adaptedfor topical administration to the eye include eye drops wherein theactive ingredient is dissolved or suspended in a suitable carrier,especially an aqueous solvent. Pharmaceutical compositions adapted fortopical administration in the mouth include lozenges, pastilles andmouth washes. Pharmaceutical compositions adapted for rectaladministration may be presented as suppositories or enemas.

Pharmaceutical compositions adapted for nasal administration wherein thecarrier is a solid include a coarse powder having a particle size forexample in the range 20 to 500 microns which is administered in themanner in which snuff is taken, i.e. by rapid inhalation through thenasal passage from a container of the powder held close up to the nose.Suitable compositions wherein the carrier is a liquid, foradministration as a nasal spray or as nasal drops, include aqueous oroil solutions of the active ingredient.

Pharmaceutical compositions adapted for administration by inhalationinclude fine particle dusts or mists which may be generated by means ofvarious types of metered dose pressurised aerosols, nebulizers orinsufflators.

Pharmaceutical compositions adapted for vaginal administration may bepresented as pessaries, tampons, creams, gels, pastes, foams or sprayformulations.

Pharmaceutical compositions adapted for parenteral administrationinclude aqueous and non-aqueous sterile injection solution which maycontain anti-oxidants, buffers, bacteriostats and solutes which renderthe formulation substantially isotonic with the blood of the intendedrecipient; and aqueous and non-aqueous sterile suspensions which mayinclude suspending agents and thickening agents. Excipients which may beused for injectable solutions include water, alcohols, polyols,glycerine and vegetable oils, for example. The compositions may bepresented in unit-dose or multi-dose containers, for example sealedampoules and vials, and may be stored in a freeze-dried (lyophilized)condition requiring only the addition of the sterile liquid carried, forexample water for injections, immediately prior to use. Extemporaneousinjection solutions and suspensions may be prepared from sterilepowders, granules and tablets.

The pharmaceutical compositions may contain preserving agents,solubilising agents, stabilising agents, wetting agents, emulsifiers,sweeteners, colourants, odourants, salts (substances of the presentinvention may themselves be provided in the form of a pharmaceuticallyacceptable salt), buffers, coating agents or antioxidants. They may alsocontain therapeutically active agents in addition to the substance ofthe present invention.

Dosages of the substance of the present invention can vary between widelimits, depending upon the disease or disorder to be treated, the ageand condition of the individual to be treated, etc. and a physician willultimately determine appropriate dosages to be used.

The dosage depends on a variety of factors including the age, weight andcondition of the patient and the route of administration. The dosage fora particular patient will be determined by a physician. Typically,however, the dosage adopted for each route of administration when acompound of the invention is administered to adult humans is 0.001 to500 mg/kg, most commonly in the range of 0.01 to 100 mg/kg, body weight,for instance, 0.01 to 50 mg/kg. Such a dosage may be given, for example,from 1 to 5 times daily by bolus infusion, infusion over several hoursand/or repeated administration. The dosage and timing of administrationof, for example, another chemotherapeutic or antineoplastic agent whichmay be given to a cancer patient with a compound of the invention willsimilarly be dependent on a variety of factors and will be determined bya physician.

A compound of formula (I) or a pharmaceutically acceptable salt thereofis formulated for use as a pharmaceutical composition also comprising apharmaceutically acceptable carrier or diluent. The compositions aretypically prepared following conventional methods and are administeredin a pharmaceutically suitable form. Preferred pharmaceuticalcompositions are sterile and pyrogen-free. Further the pharmaceuticalcompositions provided by the invention typically contain a compound ofthe invention which is a substantially pure optical isomer.

Compositions suitable for oral administration may, if required, containa colouring or flavouring agent. Typically, a capsule or tabletcomprises from 5 to 500 mg, preferably 10 to 500 mg, more preferably 15to 100 mg, of a compound of formula (I) or a pharmaceutically acceptablesalt thereof.

This dosage may be repeated as often as appropriate. If side effectsdevelop the amount and/or frequency of the dosage can be reduced, inaccordance with normal clinical practice.

The compositions may be administered in conjunction with otherpharmaceutically active compounds, especially those effective fortreating cancers. The other active compounds may be incorporated in thesame composition as the compounds of the present invention or they maybe administered alongside the compounds of the present invention, e.g.simultaneously or sequentially.

According to a fifth aspect of the invention there is provided acompound of general formula (I) for use in medicine.

Without wishing to be bound by theory, it is believed that the HDACinhibitors of the present invention comprise a cap moiety, a linker (thegroup Q) and a zinc binding group (the hydroxamic acid group C(O)V). Thezinc binding group binds to zinc in the HDAC receptor pocket in cells,while the cap moiety binds at the rim of the pocket and the linker groupQ provides a linkage corresponding to the depth of the pocket to allowthe cap moiety to bind around the pocket rim. The addition of the secondsidechain in the cap moiety, especially lying in a different plane tothe other chain of the cap moiety provides we believe tighter binding ofthe HDAC inhibitor in the receptor pocket. FIG. 7 shows the schematicbinding of prior art SAHA (left hand drawing) in an HDAC catalyticpocket and the centre and the right hand drawings show the binding ofcompounds of the present invention in the same pocket.

The compounds of the present invention find greatest application inmedical treatment in the field of cancer. For example, in the treatmentof cancerous tumour growths, particularly solid tumours. However, itthey may also have application in the treatment of other diseases andconditions the etiology of which involves gene transcription that issuppressed by HDAC enzymes.

Therapeutic substances of the present invention may be used in thetreatment of a human or non-human animal. The treatment may beprophylactic or may be in respect of an existing condition. For example,in the treatment of cancer, including breast cancer, colon cancer,colorectal cancer, esophageal cancer, glioma, lung small and non-smallcell cancers, leukaemia neuroblastoma, prostate cancer, thoracic cancer,melanoma, ovarian cancer, cervical cancer and renal cancer; cardiachypertrophy, as well as haematological disorders includinghemoglobinopathies, thalessemia, and sickle cell anemia, auto-immunediseases, such as arthritis, Huntington's disease, and neurologicalconditions, such as Alzheimer's disease, and genetic-related metabolicdisorders, such as cystic fibrosis, peroxisome biogenesis disorders andadrenoleukodystrophy. HDAC inhibitors have been proposed for stimulatinghematopoietic cells ex vivo, ameliorating protozoal parasitic infection,accelerating wound healing and protecting hair follicles. Thus thesubstances of the present invention may be used in the manufacture of amedicament for the treatment of one or more of the above-mentioneddiseases/disorders.

A use in accordance with this aspect is the use of a compound of generalformula (I) in the manufacture of a medicament for the treatment ofcancer.

A compound of the invention may be used in combination with anotherchemotherapeutic or antineoplastic agent in the treatment of cancer. Forexample, mitoxantrone, Vinca alkaloids, such as vincristine andvinblastine, anthracycline antibiotics such as daunorubicin anddoxorubicin, alkylating agents such as chlorambucil and melphalan,taxanes such as paclitaxel, anti-folates such as methotrexate andtomudex, epipodophyllotoxins such as etoposide, camptothecins such asirinotecan and its active metabolite SN-38, DNA methylation inhibitors,alkylating agents such as cyclophosphamide and platinum compounds suchas cisplatin and oxaliplatin.

The compounds of the present invention may therefore be administered asa kit of parts with a chemotherapeutic or anti-neoplastic agent asdefined above as a combined preparation for simultaneous, separate orsequential use in treating cancer. The compound of the invention may beadministered together or, if separately, in any order as determined by aphysician.

This aspect of the invention therefore extends to a method of treatmentof an individual suffering from a disease condition, the methodcomprising administering to the individual a therapeutically effectiveamount of a compound of general formula (I).

According to a seventh aspect of the present invention, there isprovided a method of inhibition of histone deacetylase activity in anindividual suffering from a disease condition, the method comprisingadministering to the individual a therapeutically effective amount of acompound of general formula (I).

The inhibition may be defined as any reduction in the activity ofhistone deacetylase activity in the individual. The reduction may befrom an elevated level of activity to a normal level in the subject, orit may even be a reduction to below what would be considered as thenormal activity in the subject.

Features for the second and subsequent aspects of the invention are asfor the first aspect mutatis mutandis.

The invention will now be further described by way of reference to thefollowing Examples which are provided for the purposes of illustrationonly and are not to be construed as being limiting on the invention.

BRIEF DESCRIPTION OF DRAWINGS

FIGS. 1 to 3 show graphs of the HDAC activity of a test compoundaccording to the present invention and another compound according to theprior art;

FIG. 4 shows changes in the acetylation state of histone H3 with a testcompound according to the present invention and another compoundaccording to the prior art;

FIG. 5 shows changes in histone H3 acetylation with time in MCF7 cellsexposed to no drug, a compound according to the prior art and a testcompound according to the present invention;

FIG. 6 shows the effect of a compound according to the prior art and atest compound according to the present invention on the growth of breastcancer tumours in mice; and

FIG. 7 is a schematic drawing showing the binding of a compoundaccording to the prior art and two test compounds according to thepresent invention in an HDAC catalytic pocket.

EXPERIMENTAL SECTION Synthesis of Compounds

Starting materials were purchased from Avocado or Aldrich and used assupplied, unless otherwise stated.

5-Chloro-3-methyl-1,2,4thiadiazole was prepared by condensation ofacetamidine with trichloromethanesulfenyl chloride according to theprocedure of A. M. MacLeod, R. Baker, S. B. Freedman, S. Patel et al.,J. Med. Chem. 1990, 33, 2052.

2-tert-Butoxycarbonyloctanedioate 1-tert-butyl ester 8-ethyl ester(14a). To a suspension of sodium hydride (0.11 g, 2.78 mmol) in THF (5mL) at 0° C. was added a solution of di-tert-butyl malonate (0.53 mL,0.5 g, 2.31 mmol) in THF (1.5 mL). The mixture was warmed to roomtemperature and stirred for 10 min. To the mixture was slowly added asolution of ethyl 6-bromohexanoate (0.42 mL, 0.52 g, 2.31 mmol) in THF(0.5 mL) and the mixture was stirred at 70° C. for 10 hours. Afterdilution of the mixture with ethyl acetate (10 mL), the solution waswashed with water (20 mL) and brine (20 mL), dried over MgSO₄ andevaporated. The residue was purified by chromatography on silica gel(80:20 petroleum ether 60-80° C.:ethyl acetate) to give the2-tert-butoxycarbonyloctanedioate 1-tert-butyl ester 8-ethyl ester (14a)as a clear oil (0.61 g, 74%); R_(f)=0.33 (5:1 petroleum ether 60-80°C.:ethyl acetate); ¹H NMR (300 MHz, CDCl₃): δ 4.11 (2H, q, J=7.2 Hz,OCH₂CH₃), 3.37 (1H, t, J=5.7 Hz, COCH), 2.27 (2H, t, J=7.1 Hz, CH₂CO),1.87 (2H, br m, CHCH₂CH₂CH₂CH₂), 1.46 (2H, t, J=7.6 Hz, CHCH₂), 1.37(4H, br m, CHCH₂CH₂CH₂), 1.22 (3H, t, J=7.2 Hz, OCH₂CH₃), 1.43 (18H, s,C(CH₃)₃); ¹³C NMR (75 MHz, CDCl₃): δ 173.93 (CO), 173.93 (CO), 171.15(CO), 61.14 (OCH₂CH₃), 51.66 (COCH), 33.89 (CH₂CO), 29.44 (CH(CH₃)₃),28.91 (CHCH₂CH₂CH₂), 28.27 (CHCH₂CH₂), 26.83 (CHCH₂CH₂CH₂CH₂), 24.46(CHCH₂), 14.17 (OCH₂CH₃).

8-Ethyl-2-carboxyoctanedioic acid (15a).2-tert-butoxycarbonyl-octanedioic acid 1-tert-butyl ester 8-ethyl ester(14a) (0.80 g, 2.23 mmol) was dissolved in a mixture of glacial aceticacid and TFA (56 mL, 1:1 v/v) and stirred for 16 hours at roomtemperature. The solution was diluted with toluene (30 mL) andevaporated. The residual oil was dissolved in ether (20 mL) and thesolution washed with water (20 mL), then concentrated to give a darkorange oil that crystallised overnight. Recrystallisation fromisopropanol afforded 8-ethyl-2-carboxyoctanedioic acid (15a) (0.30 g,58%) as a white crystalline solid; R_(f)=0.27 (ethyl acetate); ¹H NMR(300 MHz, CDCl₃): δ 9.85 (2H, s, OH), 4.14 (2H, q, J=7.4 Hz, OCH₂CH₃),3.38 (1H, t, J=5.9 Hz, COCH), 2.29 (2H, t, J=7.3 Hz, CH₂CO), 1.88 (2H,br m, CHCH₂CH₂CH₂CH₂), 1.44 (2H, t, J=7.8 Hz, CHCH₂), 1.35 (4H, br m,CHCH₂CH₂CH₂), 1.22 (3H, t, J=7.3 Hz, OCH₂CH₃); ¹³C NMR (75 MHz, CDCl₃):δ 180.03 (CO), 174.30 (CO), 60.65 (OCH₂CH₃), 51.47 (COCH), 34.18(CH₂CO), 28.55 (CHCH₂CH₂CH₂), 28.46 (CHCH₂CH₂), 26.79 (CHCH₂CH₂CH₂CH₂),24.50 (CHCH₂), 14.12 (OCH₂CH₃).

7,7-Bis-phenylcarbamoyl-heptanoic acid ethyl ester (16a). Thionylchloride (1.97 mL, 3.22 g, 27.1 mmol) was added dropwise to a stirredsolution 8-ethyl-2-carboxyoctanedioic acid (15a) (1.10 g, 4.5 mmol) indry benzene (25 mL) and was then heated at reflux for 2.5 hours. Themixture was allowed to cool to room temperature and then evaporated togive an off-white solid. This crude acid chloride was dissolved indichloromethane (10 mL) and added dropwise to a vigorously stirredmixture of aniline (2.5 mL, 2.5 g, 27.1 mol), pyridine (1.07 g, 13.5mol) and dichloromethane (15 mL). The resulting solution was stirred atroom temperature for 17 hours. The aqueous layer was extracted withdichloromethane (3×40 mL) and the organic extracts combined with theoriginal organic layer to give a solution that was washed with water (40mL), dried (MgSO₄), filtered and evaporated. The residue was purified byflash column chromatography (75:25 petroleum ether 60-80° C.:ethylacetate) to give 7,7-bis-phenylcarbamoyl-heptanoic acid ethyl ester(16a) as a white crystalline solid (1.30 g, 76%); R_(f)=0.47 (3:1,petroleum ether 60-80° C.:ethyl acetate); ¹H NMR (300 MHz, CDCl₃): δ7.59 (4H, d, J=7.6 Hz, Ar—H), 9.93 (2H, s, NH), 7.30 (4H, t, J=8.2 Hz,Ar—H), 7.04 (2H, t, J=7.4 Hz, Ar—H), 4.01 (2H, q, J=7.1 Hz, OCH₂CH₃),3.46 (1H, t, J=7.3 Hz, COCH), 2.56 (2H, t, J=7.3 Hz, CH₂CO), 1.88 (2H,br m, CHCH₂CH₂CH₂CH₂), 1.52 (2H, t, J=7.0 Hz, CHCH₂), 1.42 (3H, t, J=7.1Hz, OCH₂CH₃), 1.30 (4H, br m, CHCH₂CH₂CH₂); ¹³C NMR (75 MHz, CDCl₃): δ173.70 (CO), 169.77 (CO), 137.53 (quaternary Ar—C), 128.99 (Ar—C—H),124.82 (Ar—C—H), 120.32 (Ar—C—H), 60.29 (OCH₂CH₃), 56.26 (COCH), 34.08(CH₂CO), 33.35 (CHCH₂CH₂CH₂), 28.52 (CHCH₂), 27.17 (CHCH₂CH₂), 24.52(CHCH₂CH₂CH₂CH₂), 14.22 (OCH₂CH₃).

7,7-Bis-phenylcarbamoyl-heptanoic acid (16b). A solution of lithiumhydroxide monohydrate (0.17 g, 4.05 mmol) in water (5 mL) was added to astirred solution of 7,7-bis-phenylcarbamoyl-heptanoic acid ethyl ester(16a) (1.07 g, 2.7 mmol) in ethanol (50 mL) at 0° C. The mixture wasallowed to warm to room temperature and stirred for 16 hours. Thesolvent was removed under reduced pressure and the resulting residue wastaken up in water (50 mL), washed with ethyl acetate (60 mL) andacidified with 1 M hydrochloric acid. The aqueous layer was extractedwith ethyl acetate (3×60 mL), and the combined extracts were dried(MgSO₄), filtered and organic solvent evaporated to give7,7-bis-phenylcarbamoyl-heptanoic acid (16b) as a white solid (0.95 g,95%); R_(f)=0.25 (3:1, petroleum ether 60-80° C.:ethyl acetate); ¹H NMR(300 MHz, CDCl₃): δ 9.83 (2H, s, NH), 7.56 (4H, d, J=7.8 Hz, Ar—H), 7.32(4H, t, J=8.1 Hz, Ar—H), 7.14 (2H, t, J=7.6 Hz, Ar—H), 3.43 (1H, t,J=7.2 Hz, COCH), 2.58 (2H, t, J=7.1 Hz, CH₂CO), 1.86 (2H, br m,CHCH₂CH₂CH₂CH₂), 1.49 (2H, t, J=7.1 Hz, CHCH₂), 1.33 (4H, br m,CHCH₂CH₂CH₂); ¹³C NMR (75 MHz, CDCl₃): δ 172.10 (CO), 170.17 (CO),137.13 (quaternary Ar—C), 128.73 (Ar—C—H), 124.68 (Ar—C—H), 120.52(Ar—C—H), 56.32 (COCH), 34.18 (CH₂CO), 33.43 (CHCH₂CH₂CH₂), 28.32(CHCH₂), 27.23 (CHCH₂CH₂), 24.54 (CHCH₂CH₂CH₂CH₂).

2-Phenylcarbamoyl-octanedioic acid 8-hydroxyamide 1-phenylamide (C1, orUCL67022)

Method A. To a stirred solution of 7,7-bis-phenylcarbamoyl-heptanoicacid (16b) (0.20 g, 0.54 mmol) at room temperature in anhydrous DMF (3mL) was added 1-hydroxybenzotriazole (0.10 g, 0.69 mmol) followed by1-ethyl-3-[3-(dimethylamino)propyl]carbodiimide (0.16 g, 0.82 mmol).After 1 h, hydroxylamine hydrochloride (0.042 g, 0.6 mmol) andtriethylamine (0.084 mmol, 0.061 g, 0.6 mmol) were added, and stirringwas continued at room temperature for 16 hours. The solvent wasevaporated and the residue was diluted with ethyl acetate (10 mL). Thesolution was washed with saturated aqueous sodium hydrogen carbonatethen dried (MgSO₄) and evaporated. The residue was recrystallised fromacetonitrile to give 2-phenylcarbamoyl-octanedioic acid 8-hydroxyamide1-phenylamide (C1 or UCL67022) as a white crystalline solid (0.12 g,56%); R_(f)=0.31 (3:1, petroleum ether 60-80° C.:ethyl acetate); ¹H NMR(300 MHz, CDCl₃): δ 9.96 (2H, s, NH), 8.67 (1H, s, NHOH), 7.56 (4H, d,J=8.0 Hz, Ar—H), 7.30 (4H, t, J=8.1 Hz, Ar—H), 7.04 (2H, t, J=7.2 Hz,Ar—H), 3.46 (1H, t, J=7.0 Hz, COCH), 1.93 (4H, br m, CH₂CH₂CO), 1.48(2H, br m, CHCH₂), 1.28 (4H, br m, CHCH₂CH₂CH₂); ¹³C NMR (75 MHz,CDCl₃): δ 169.01 (CO), 167.76 (CO), 138.80 (quaternary Ar—C), 128.67(Ar—C—H), 123.40 (Ar—C—H), 119.30 (Ar—C—H), 54.96 (COCH), 32.17 (CH₂CO),29.42 (CHCH₂CH₂CH₂), 28.50 (CHCH₂), 26.89 (CHCH₂CH₂CH₂CH₂), 24.96(CHCH₂CH₂). Anal. Calcd for: C, 65.78; H, 6.57; N, 10.96; O, 16.69 foundC, 66.06; H, 6.83; N, 10.67; O, 16.45%.

Method B. Sodium metal (0.053 g, 2.28 mmol) was dissolved in methanol(0.63 mL). To that solution was added a solution of hydroxylaminehydrochloride (0.11 g, 1.52 mmol) dissolved in methanol (0.73 mL); after5 min a precipitate of sodium chloride appeared. To this mixture wasthen added 7,7-bis-phenylcarbamoyl-heptanoic acid ethyl ester (3) (0.30g, 0.76 mmol) which dissolved readily, and the solution was left to stirat room temperature for 16 hours. The solvent was evaporated, and theresidue was diluted with ethyl acetate (10 mL) and THF (2 mL). Thesolution was washed with water (15 mL), dried (MgSO₄) and evaporated.The residue was recrystallised from acetonitrile to give2-phenylcarbamoyl-octanedioic acid 8-hydroxyamide 1-phenylamide (C1 orUCL67022) (0.20 g, 68%) as a white crystalline solid.

Biological Results

Methods

Activity Against Partially Purified and Intracellular HDAC Enzymes

The activity of compounds as inhibitors of histone deacetylase wasinvestigated using a modified procedure based on a rapid in vitro HDACactivity assay (HDAC mediated deacetylation of an Ω-acetylated lysine(MAL)) as described by Hoffman et al in Nucl. Acids. Res. 27 2057-2058(1999). The compounds investigated were SAHA and Compound UCL67022, andis compound C1 mentioned above:

The HDAC substrateN-(-4-methyl-7-coumarinyl)-N-α-(tert-butyloxy-carbonyl)-N-Ω abbreviatedas MAL was synthesised as described (Hoffman et al 1999). HDACinhibitors and substrate (MAL) were made up in Hepes buffer (50 mM, pH7.4). Partially purified HDAC enzyme (liver prep, 100 μL), HDACinhibitor or Hepes buffer (100 μl), substrate (MAL, 100 μL 5 μg/mL) andassay buffer (100 μL, tris-HCl (10 mM), NaCl (10 mM), MgCl₂ (15 mM),EGTA (0.1 mM), 10% (v/v) glycerol, and mercaptoethanol (0.007%)) wereincubated at 37° C. for 60 minutes. The reaction was terminated with 100μl acetonitrile, and MAL and the deacetylated product (ML) weredetermined in the supernatant.

The fluorescent substrate MAL has been used in a novel assay establishedand validated by Dr Joel for the determination of HDAC activity inintact cells. This assay has been used to determine whole cell HDACactivity in the presence of known or novel HDAC inhibitors, with asingle time-point reaction.

In this procedure 1×10⁶ CEM cells in 1 ml medium were exposed toinhibitors for 60 minutes, after which MAL at 20 μg/ml (5 μg/mL finalconcentration) was added for a further 30 minutes, all at 37° C. Cellswere then rapidly washed at 4° C., lysed by sonication, the reactionstopped with acetonitrile, and MAL and the deacetylated productdetermined in the supernatant by rapid HPLC.

Chromatographic separation of MAL and ML was carried out using a 15 cmApex ODS 5 μM column with acetonitrile/distilled water (40:60), 2%trifluoracetic acid (TFA) v/v mobile phase at a flow rate of 1.2ml/minute. MAL and ML were quantified by fluorescence detection atexcitation/emission wavelengths of 330/395 nm.

The activity of each inhibitor was assessed at a minimum of 5 non-zeroconcentrations. MAL and ML peak heights were used to derive thepercentage MAL in the mixture as the ration of MAL: MAL+ML. Thepercentage MAL in the absence of inhibitor (typically 22-25%) was takenas 100% HDAC activity, and the percentage HDAC activity at higherconcentrations derived from (100%-% MALdrug/100-% MALnodrug×100). Thesedata (minimum of n=3 at each concentration for each inhibitor) werefitted to a sigmoidal EMAX model (Graphpad Prism ver 3.03) to derive theconcentration resulting in 50% inhibition (IC₅₀) for each compound.These data show increased HDAC inhibitory activity for the compoundUCL67022 compared to SAHA, currently in clinical trials

Antiproliferative and Cytotoxic Activity in Cancer Cell Lines.

EC₅₀ values for percentage viability (3-day exposure) were determinedusing 2 different methods, trypan blue staining and an ATP assay. Trypanblue staining relies on the ability of healthy cells with intactmembranes to exclude dyes. As cells start to undergo programmed celldeath membrane integrity becomes compromised allowing dye entry. The %cells staining positive for trypan blue relative to the total cellnumber therefore reflects % cell viability (% viability). Non-viablecells also lose the ability to regenerate ATP. A specific ATP assayprocedure using a 96-well plate-based approach (Vialite assay, Cambrex,UK) also measures cell viability, expressed relative to the ATP value inthe control (untreated) cell population. For both assays cells aretreated across a range of concentrations and the resulting activity datasummarised as the drug concentration inducing 50% of maximum effect(EC₅₀).

Protein Analysis

The effect of the compounds on the acetylation of histone H3 wasinvestigated in MCF-7 cells. Briefly cells were treated with a range ofconcentration of specific inhibitor or different exposure durations.Cells were then lysed and the proteins resolved by polyacrylamideelectrophoresis prior to blotting onto a nitrocellulose membrane andstaining with an antibody specific for the protein under study(acetylated histone H3) and a control protein (β-actin). As HDACinhibitors reduce deacetylase activity, treatment of intact cellsresults in the accumulation of acetylated histones.

Xenograft Studies

Xenograft studies were carried out with MCF7 cells implanted under theskin on the flank of female nude mice (5-8 weeks of age). When tumoursof at least 100 mm³ were measurable animals were randomised to receivedaily IP injections of SAHA (reference compound), the test compoundUCL67022 or vehicle control. Animals also received a 2 mg oestrogenpellet as an implant on the day of tumour implantation. Tumour volumeswere determined from measurements of 2 diameters carried out every otherday out to day 15 of treatment.

Results

HDAC Inhibitory Activity

The HDAC inhibitory activity of compound UCL67022 and the referencecompound SAHA in a partially purified rat liver preparation are shown inFIG. 1. IC₅₀ values were 0.05±0.01 μM for UCL67022 and 0.39±0.05 μM forSAHA.

In intact CEM cells HDAC inhibitory values were 0.11±0.02 μM forUCL67022 and 0.33±0.05 μM for SAHA, as shown in FIG. 2.

Effects on Cell Viability

The effect of 3 day incubations with compound UCL67022 or SAHA across arange of concentrations in CEM (leukaemic), HCT116 (colorectal cancer)and MCF7 (breast cancer) cells is shown in FIG. 3. Compound UCL67022 wassubstantially more active than SAHA in this model system, with EC₅₀values of 0.06 vs 1.7 μM respectively in CEM cells, 0.07 vs 1.0 μMrespectively in HCT116 cells and 0.13 vs 1.9 μM respectively in MCF7cells (FIG. 3). In a panel of 8 lymphoma cell lines EC₅₀ values usingthe same endpoint assay (ATP) ranged from 0.76 to 1.28 μM for SAHA(median μM) and 0.02 to 0.08 μM for compound UCL67022 (median μM).

Protein Studies

The effect of drug concentration and exposure duration to SAHA orcompound UCL67022 on histone H3 acetylation was studied in MCF7 cells.FIG. 4 shows the results of these tests, where the top line shows thetotal quantity of Histone H3 (both acetylated and deacetylated) after a2-hour exposure to increasing concentrations of SAHA or compoundUCL67022 while the bottom line shows the equivalent results for acetylhistone H3; in FIG. 4, the darker the blots, the higher is the amount ofthe histone concerned. Compound UCL67022 resulted in a marked change inhistone H3 acetylation at concentrations as low as 0.1 μM after a 2 hourexposure, whereas SAHA exposure resulted in relatively minor changes inacetylation state at concentrations <1.0 μM.

Cells were then exposed to equipotent concentrations of SAHA (3 μM) orcompound UCL67022 (0.3 μM) for time periods up to 48 hours and cellsamples collected at regular time intervals for protein studies (FIG.5). In the absence of either drug little change in histone H3acetylation was observed. With 3 μM SAHA H3, acetylation increased up to6 hours, but had decreased to baseline levels by 24 hours. Note that theSAHA sample at 9 hours showed a decreased loading based on the β-actinband and should be ignored. With 0.3 μM UCL67022 H3, acetylationcontinued to increase out to 24 hours, and was still substantiallyhigher than baseline at 48 hours. These data confirm the potencyincrease of compound UCL67022 over SAHA and suggest this compound may bemore stable, and thus longer acting, than SAHA in cell cultureconditions.

Xenograft Studies

A 15 day treatment of MCF7 (breast cancer) tumours in nude mice withdaily IP dosing was carried out with SAHA at a daily dose of 25 mg/kg inDMSO (vehicle). The results are shown in FIG. 6. In this study, thegrowth of the tumour with the SAHA was not very different to treatmentwith the DMSO vehicle alone. This dose of SAHA has previously been shownto reduce tumour volumes in a prostate cancer xenograft, but clearly wasnot effective in this tumour model. In contrast, the same treatment withcompound UCL67022 at daily dose levels less than SAHA (12.5·M and6.25·M) appeared to have a clear effect on tumour growth (see FIG. 6)

Example 2

The HDAC inhibitory activity of three further compounds in accordancewith the present invention were tested; these compounds were as follows

Synthesis of Compounds Preparation of2-(3-Methyl[1,2,4]thiadiazol-5-yl)octanedioic Acid 8-Hydroxyamide1-Phenylamide (Compound 67022.6, which is Also Referred to as Compound2021032 Below)

The overall reaction scheme is as follows:

Preparation of 5-Chloro-3-methyl-1,2,4-thiadiazole (2009380)

To a stirred mixture of acetamidine hydrochloride (38.1 g, 0.40 mol) andtrichloromethanesulfenyl chloride (75 g, 0.40 mol) at −5° C. was addeddropwise over 2.5 h a solution of NaOH (75.7 g, 0.40 mol) in water (126mL). The resultant reaction mixture was then stirred at 0° C. for 30 minbefore being allowed to warm to room temperature. The mixture wassubsequently filtered, the layers were separated, and the aqueous phasewas extracted with dichloromethane (3×150 mL). The combined organicfractions were washed with brine (2×150 mL), dried (MgSO₄), and thesolvent was removed under reduced pressure to afford5-chloro-3-methyl-1,2,4-thiadiazole (2009380) (43 g, 83%) as a dark oil.

Preparation of 2-tert-Butoxycarbonyloctanedioic acid 1-tert-Butyl Ester8-Ethyl Ester (2021037)

Potassium tert-butoxide (12.3 g, 0.11 mol) followed by di-tert-butylmalonate (21.6 g, 0.10 mol) was added portionwise to stirredtetrahydrofuran (150 mL) then ethyl-6-bromo hexanoate (22.8 g, 0.102mol) was added to the resultant yellow slurry. The mixture was stirredat room temperature for 48 h before being quenched with a solution ofcitric acid (30 g) in water (150 mL) and extracted with dichloromethane(3×200 mL). The combined organic fractions were dried (MgSO₄) and thesolvent was removed under reduced pressure to afford2-tert-butoxycarbonyloctanedioic acid 1-tert-butyl ester 8-ethyl ester(2021037) (34.4 g, 96%) as a clear oil.

Preparation of2-tert-Butoxycarbonyl-2-(3-methyl[1,2,4]thiadiazol-5-yl)octanedioic Acid1-tert-Butyl Ester 8-Ethyl Ester (2021038)

Potassium tert-butoxide (12.2 g, 0.11 mol) followed by2-tert-butoxycarbonyloctanedioic acid 1-tert-butyl ester 8-ethyl ester(2021037) (30.0 g, 83.8 mmol) was added portionwise to stirredtetrahydrofuran (170 mL) and then 5-chloro-3-methyl-1,2,4-thiadiazole(2009380) (11.3 g, 83.8 mmol) was added to the resultant slurry. Themixture was heated at reflux overnight before being quenched with water(150 mL) and extracted with dichloromethane (3×200 mL). The combinedorganic fractions were dried (MgSO₄) and the solvent was removed underreduced pressure. The crude product was purified by flash chromatography(6:1 hexane/ethyl acetate) to afford2-tert-butoxycarbonyl-2-(3-methyl[1,2,4]thiadiazol-5-yl)octanedioicaAcid 1-tert-butyl ester 8-ethyl ester (2021038) (10 g, 26%) as a yellowoil.

Preparation of 2-(3-Methyl[1,2,4]thiadiazol-5-yl)octanedioic Acid8-Ethyl Ester (2021039)

To stirred trifluoroacetic acid (20 mL) was added2-tert-butoxycarbonyl-2-(3-methyl[1,2,4]thiadiazol-5-yl)octanedioicaAcid 1-tert-butyl ester 8-ethyl ester (2021038) (0.75 g, 1.6 mmol) andthe resultant reaction mixture was stirred at room temperature for 1.5h. The TFA was subsequently removed under reduced pressure while thetemperature of the water bath was maintained below 25° C. The resultantoil was dissolved in dichloromethane (20 mL) and made basic with thecareful addition of triethylamine, while the temperature of the mixturewas kept below 20° C. The resultant solution of2-(3-methyl[1,2,4]thiadiazol-5-yl)octanedioic acid 8-ethyl ester(2021039) was then used immediately in the next step.

Preparation of 7-(3-Methyl[1,2,4]thiadiazol-5-yl)-7-phenylcarbamoylHeptanoic Acid Ethyl Ester (2021040)

To a stirred mixture ofO-(1H-benzotriazol-1-yl)-N,N,N′,N′-tetramethyluroniumhexafluorophosphate (0.56 g, 1.48 mmol) and aniline (0.13 g, 1.35 mmol)in dichloromethane (10 mL) was added over 5 min the solution of crude2-(3-methyl[1,2,4]thiadiazol-5-yl)octanedioic acid 8-ethyl ester(2021039) and triethylamine in dichloromethane. The resultant reactionmixture was then stirred at room temperature overnight before beingquenched with citric acid (5 g) in water (50 mL) and extracted withdichloromethane (3×50 mL). The combined organic fractions were dried(MgSO₄) and the solvent was removed under reduced pressure. The crudeproduct was purified by flash chromatography (3:1 hexane/ethyl acetatefollowed by 1:1 hexane/ethyl acetate) to afford7-(3-methyl[1,2,4]thiadiazol-5-yl)-7-phenylcarbamoyl heptanoic acidethyl ester (2021040) (310 mg, 52% over two steps) as a yellow oil.

Preparation of 2-(3-Methyl[1,2,4]thiadiazol-5-yl)octanedioic Acid8-Hydroxyamide 1-Phenylamide (2021032)

To a stirred mixture of7-(3-methyl[1,2,4]thiadiazol-5-yl)-7-phenylcarbamoyl heptanoic acidethyl ester (2021040) (300 mg, 0.80 mmol) in 50% hydroxylamine/water (20mL) was added methanol until the oil dissolved. The solution was thenheated at reflux overnight. Water (100 mL) was added and the solutionwas extracted with ethyl acetate (3×150 mL). The combined organicfractions were dried (MgSO₄) and the solvent was removed under reducedpressure. The crude product (140 mg, 0.38 mmol) was purified bypreparative liquid chromatography to afford2-(3-methyl[1,2,4]thiadiazol-5-yl)octanedioic acid 8-hydroxyamide1-phenylamide (2021032) as a yellow oil.

7-(N-Hydroxycarbamimidoyl)-2(3-methyl[1,2,4]thiadiazol-5-yl)heptanoicAcid Phenylamide (Compound 67022,19, which is Also Referred to asCompound 2021035 Below)

The overall reaction scheme is:

Preparation of 2-(5-Cyanopentyl)malonic Acid Di-tert-butyl Ester(2021050)

Potassium tert-butoxide (13.5 g, 0.12 mol) followed by di-tent-butylmalonate (21.6 g, 0.10 mol) was added portionwise to stirredtetrahydrofuran (200 mL) then 6-bromohexanenitrile (18.0 g, 0.10 mol)was added to the resultant yellow slurry. The mixture was subsequentlystirred at room temperature for 48 h before being quenched with citricacid (30 g) in water (150 mL) and extracted with dichloromethane (3×200mL). The combined organic fractions were dried (MgSO₄) and the solventwas removed under reduced pressure to afford 2-(5-cyanopentyl)malonicacid di-tert-butyl ester (2021050) (32.3 g, 100%) as a clear oil.

Preparation of2-(5-Cyanopentyl)-2-(3-methyl[1,2,4]thiadiazol-5-yl)malonic AcidDi-tert-butyl Ester (2021051)

Potassium tert-butoxide (14.6 g, 0.13 mol) followed by2-(5-cyanopentyl)malonic acid di-tert-butyl ester (2021050) (32.3 g, 0.1mol) was added portionwise to stirred tetrahydrofuran (150 mL).5-Chloro-3-methyl-1,2,4-thiadiazole (2009380) (13.5 g, 0.10 mol) wasthen added to the slurry and the mixture was heated at reflux overnightbefore being quenched with water (150 mL) and extracted withdichloromethane (3×200 mL). The combined organic fractions were dried(MgSO₄) and the solvent was removed under reduced pressure. The crudeproduct was purified by flash chromatography (6:1 hexane/ethyl acetate)to afford 2-(5-cyanopentyl)-2-(3-methyl[1,2,4]thiadiazol-5-yl)malonicacid di-tert-butyl ester (2021051) (17.2 g, 42%) as a yellow oil.

Preparation of 7-Cyano-2-(3-methyl[1,2,4]thiadiazol-5-yl)heptanoic Acid(2021052)

To stirred trifluoroacetic acid (20 mL) was added2-(5-cyanopentyl)-2-(3-methyl[1,2,4]thiadiazol-5-yl)malonic aciddi-tert-butyl ester (2021051) (0.75 g, 1.83 mmol) and the resultantmixture was stirred at room temperature for 1.5 h. The TFA was thenremoved under reduced pressure, while the temperature of the water bathwas maintained below 25° C. The resultant oil was dissolved indichloromethane (20 mL) and made basic with the careful addition oftriethylamine, while keeping the reaction temperature below 20° C. Thedichloromethane solution of7-cyano-2-(3-methyl[1,2,4]thiadiazol-5-yl)heptanoic acid (2021052) wasthen immediately used in the next step.

Preparation of 7-Cyano-2-(3-methyl[1,2,4]thiadiazol-5-yl)heptanoic AcidPhenylamide (2021044)

To a stirred mixture ofO-(1H-benzotriazol-1-yl)-N,N,N′,N′-tetramethyluroniumhexafluorophosphate (0.63 g, 1.64 mmol) and aniline (0.14 g, 1.5 mmol)in dichloromethane (10 mL) was added over 5 min the crude solution of7-cyano-2-(3-methyl[1,2,4]thiadiazol-5-yl)heptanoic acid (2021052) andtriethylamine. The resultant reaction mixture was then stirred at roomtemperature overnight before being quenched with citric acid (5 g) inwater (50 mL) and extracted with dichloromethane (3×50 mL). The combinedorganic fractions were dried (MgSO₄) and the solvent was removed underreduced pressure. The crude product was purified by flash chromatography(3:1 hexane/ethyl acetate followed by 1:1 hexane/ethyl acetate) toafford 7-cyano-2-(3-methyl[1,2,4]thiadiazol-5-yl)heptanoic acidphenylamide (2021044) (440 mg, 73% over two steps) as a yellow oil.

Preparation of7-(N-Hydroxycarbamimidoyl)-2-(3-methyl-[1,2,4]thiadiazol-5-yl)-heptanoicAcid Phenylamide (2021035)

To a stirred mixture of7-cyano-2-(3-methyl[1,2,4]thiadiazol-5-yl)heptanoic acid phenylamide(2021044) (440 mg, 1.30 mmol) in 50% hydroxylamine/water (20 mL) wasadded methanol until the oil dissolved. The solution was then heated atreflux overnight. Water (100 mL) was added and the reaction mixture wasthen extracted with ethyl acetate (3×150 mL). The combined organicfractions were dried (MgSO₄) and the solvent was removed under reducedpressure. The crude product (400 mg, 1.1 mmol) was purified bypreparative liquid chromatography to afford7-(N-hydroxycarbamimidoyl)-2-(3-methyl-[1,2,4]thiadiazol-5-yl)-heptanoicacid phenylamide (2021035) as a white solid.

2-(3-Methyl-[1,2,4]thiadiazol-5-yl)-7-thiocarbamoylheptanoic AcidPhenylamide (Compound 67022,20, which is Also Referred to as Compound2021036 Below)

To a stirred mixture of7-cyano-2-(3-methyl[1,2,4]thiadiazol-5-yl)heptanoic acid phenylamide(2021044) (0.55 g, 1.7 mmol) in pyridine (120 mL) and piperidine (30 mL)was slowly bubbled hydrogen sulphide for 15 min. The resultant mixturewas then stoppered and stirred at 50° C. for five days. The solvent wasremoved under reduced pressure, water (150 mL) was added to the residue,and the resultant solution was extracted with dichloromethane (3×150mL). The crude product (1.6 g) was purified by preparative liquidchromatography to afford2-(3-methyl-[1,2,4]thiadiazol-5-yl)-7-thiocarbamoyl heptanoic acidphenylamide (2021036) as a white solid.

Biological Activity

The activity of compounds 60755,6, 60722,19 and 60722,20 were comparedto SAHA in HDAC activity assays conducted as previously described andadditionally using a commercial HDAC assay kit (Upstate Cell SignalingSolutions, Lake Placid, N.Y., USA) and cell viability studies.

Cell-Free (Liver) HDAC Inhibitory Activity

HDAC inhibitory activity against cell-free HDACs isolated from rat liverwas determined using the HPLC method. This was with a different liverpreparation than used previously, such that the results differ slightlyfrom those shown under Example 1. SAHA and 67022 have been used on bothoccasions, with SAHA acting as the positive control for comparativepurposes. The HPLC liver results are summarised below.

Compound HDAC inhibitory IC₅₀ (μM) SAHA 0.263 ± 0.03 67022  0.04 ± 0.00967022,6  0.05 ± 0.005 67022,19 44.6 ± 5.6 67022,20 318Cell-free (CEM Cells) HDAC Inhibitory Activity

HDAC inhibitory activity has also been determined using a fluorescentcommercial kit method (Upstate Cell Signaling). The results aresummarised below.

Compound HDAC inhibitory IC₅₀ (μM) SAHA 0.282 ± 0.050 67022 0.086 ±0.007 67022,6 0.047 ± 0.006 67022,19 46.1 ± 12.0 67022,20 NDCytotoxic Activity Against CEM (Leukaemic) Cells

Effects against viable cell number have been determined using the ATPVialite kit method (Cambrex, UK). Results are shown below.

Compound HDAC inhibitory IC₅₀ (μM) SAHA 1.30 ± 0.29 67022 0.098 ± 0.04267022,6 0.220 ± 0.080

1. A compound of general formula (I):

in which: R¹ is (C₆ or C₁₀) aryl or 6- to 10-membered heteroaryl,optionally substituted with 1, 2 or 3 substituents, the substituentsbeing selected from (C₁-C₁₀) alkyl, (C₁-C₁₀) alkenyl, (C₁-C₁₀) alkynyl,(C₁-C₁₀) alkoxy, (C₁-C₁₀) thioalkoxy, hydroxyl, (C₁-C₁₀) hydroxyalkyl,halo, (C₁-C₁₀) haloalkyl, amino, amido, (C₁-C₁₀) alkylamino, (C₁-C₁₀)alkylcarbonyloxy, (C₁-C₁₀) alkoxycarbonyl, (C₁-C₁₀) alkylcarbonyl,(C₁-C₁₀) alkylthiocarbonyl, (C₁-C₁₀) alkylsulfonylamino, aminosulfonyl,(C₁-C₁₀) alkylsulfinyl, and (C₁-C₁₀) alkylsulfonyl, R² and R³ are linkedtogether and such that, together with the intervening atoms, they form a5, 6 or 7-membered aromatic or partially saturated ring containing oneor more heteroatoms, which ring may be fused to further rings as part ofa fused ring system, and which may bear 1, 2 or 3 substituents, whichsubstituents independently have the same meaning as R^(2′) on any or allof those rings, Q stands for (C₁-C₈) alkyl that optionally includes asingle double bond, which may be in the position adjacent to thecarbonyl group, and is optionally interrupted by a C₆ aryl ring; (C₂-C₆)alkenyl or (C₂-C₆) alkynyl comprising one or more C═C bond or C≡C bond;V is OH, SH, SR, OR, NH₂, NHR, NRR, NROH, NHOR, NROR where R mayindependently be hydrogen or (C₁-C₆) alkyl, Y is N; Z is O, S, S(═O),S(═O)₂, NR⁴, —N═, CR⁴R⁵, or —C(R⁴)═, where R⁴ and R⁵ independently havethe same meaning as R^(2′); and R^(2′) is hydrogen, (C₁-C₆) alkyl,substituted (C₁-C₆) alkyl, or unsaturated (C₂-C₆) alkenyl or alkynylcomprising one or more C═C bond or C≡C bonds, (C₆ or C₁₀) aryl or 6- or10-membered heteroaryl, or a combination thereof to form a linked orfused ring system, (C₁-C₆) alkoxy, (C₁-C₆) thioalkoxy, hydroxyl, (C₁-C₆)hydroxyalkyl, halo, (C₁-C₆) haloalkyl, cyano, nitro, amino, amido,(C₁-C₆) alkylamino, (C₁-C₆) alkylcarbonyloxy, (C₁-C₆) alkoxycarbonyl,(C₁-C₆) alkylcarbonyl, (C₁-C₁₀) alkylthiocarbonyl, (C₁-C₆)alkylsulfonylamino, aminosulfonyl, (C₁-C₆) alkylsulfinyl, or (C₁-C₆)alkylsulfonyl; or a tautomeric form thereof, or a pharmaceuticallyacceptable salt thereof.
 2. A compound as claimed in claim 1 where Qstands for C₁₋₈ alkyl that optionally includes a single double bond,which may be in the position adjacent to the carbonyl group, and isoptionally interrupted by a C₆ aryl ring, or a tautomeric form thereof,or a pharmaceutically acceptable salt thereof.
 3. A compound as claimedin claim 1, in which the compound of general formula (I) has the formula(Ia)

or a tautomeric form thereof, or a pharmaceutically acceptable saltthereof.
 4. A compound as claimed in claim 1, in which R² and R³ arelinked by two atoms W—X where W and X are independently O, S, S(═O),S(═O)₂, NR⁴, —N═, CR⁴R⁵, or —C(R⁴)═, where R⁴ and R⁵ each independentlyhas the same meaning as R², and where the linkage between W and X, andbetween X and Z are either both single bonds, or one single bond and onedouble bond, or a tautomeric form thereof, or a pharmaceuticallyacceptable salt thereof.
 5. A compound as claimed in claim 4, in which Vis —OH, —OC₂H₅, —OCH₃, or —NHOH, or a tautomeric form thereof, or apharmaceutically acceptable salt thereof.
 6. A compound of generalformula (A)

in which: W, X and Z are independently O, S, S(═O), S(═O)₂, NR⁴, —N═,CR⁴R⁵, or —C(R⁴)═, where R⁴ and R⁵ may independently have the samemeaning as R^(2′) or W and X together or X and Z together form a 5 or 6membered fused ring that optionally includes one or more heteroatoms andthat optionally carry one or more substituents having the same meaningas R^(2′); the bonds between W and X, and between X and Z may be eitherboth single bonds, or one single bond and one double bond, R⁶, R⁷ and R⁸(each of which can be in any location on the ring) each independentlyhas the same meaning as R^(2′), or two of the substituents R⁶, R⁷ and R⁸are linked to form a five-, six- or seven-membered ring that is fused tothe benzene ring and that is heteroaryl, heterocycloalkenyl,cycloalkenyl, cycloalkyl or heterocycloalkyl and is either unsubstitutedor bears one, two or three substituents that each independently has thesame meaning as R^(2′), Q stands for (C₁-C₈) alkyl that optionallyincludes a single double bond, which may be in the position adjacent tothe carbonyl group, and is optionally interrupted by a C₆ aryl ring;(C₂-C₆) alkenyl or (C₂-C₆) alkynyl comprising one or more C═C bond orC≡C bond; R^(2′) is hydrogen, (C₁-C₆) alkyl, substituted (C₁-C₆) alkyl,or unsaturated (C₂-C₆) alkenyl or alkynyl comprising one or more C═Cbond or C≡C bonds, (C₆ or C₁₀) aryl or 6- or 10-membered heteroaryl, ora combination thereof to form a linked or fused ring system, (C₁-C₆)alkoxy, (C₁-C₆) thioalkoxy, hydroxyl, (C₁-C₆) hydroxyalkyl, halo,(C₁-C₆) haloalkyl, cyano, nitro, amino, amido, (C₁-C₆) alkylamino,(C₁-C₆) alkylcarbonyloxy, (C₁-C₆) alkoxycarbonyl, (C₁-C₆) alkylcarbonyl,(C₁-C₁₀) alkylthiocarbonyl, (C₁-C₆) alkylsulfonylamino, aminosulfonyl,(C₁-C₆) alkylsulfinyl, or (C₁-C₆) alkylsulfonyl; or a tautomeric formthereof, or a pharmaceutically acceptable salt thereof.
 7. A compound ofclaim 6, in which: W, X and Z are each independently O, S, NR⁴, —N═,CR⁴R⁵ or —C(R⁴)═, where R⁴ and R⁵ may independently have the samemeaning as R^(2′), the linkage between W and X, and between X and Z maybe either both single bonds, or one single bond and one double bond, R⁸stands for H, R⁷ stands for H and R⁶ is an atom or group within thedefinition of R^(2′) having 6 atoms or fewer, or a tautomeric formthereof, or a pharmaceutically acceptable salt thereof.
 8. A compound asclaimed in claim 1, in which: R² and R³ are linked in the form of theatoms or groups W—X—Y in which W, X, Y and Z may independently be O, S,S(═O), S(═O)₂, NR⁴, —N═, CR⁴R⁵, or —C(R⁴)═, where R⁴ and R⁵ may eachindependently have the same meaning as R^(2′), and Y may represent abond linking X and Z, the linkage between the pairs of atoms WX, XY andYZ (a) may all be single bonds, or (b) one of the linkages W—X, X-Y andY-Z may be double bond and the other linkages may be single bonds, or(c) linkages WX and YZ may be double bonds and linkage XY may be asingle bond, or W and X together or X and Z together form a 5 or 6membered fused ring that optionally includes one or more heteroatoms andthat optionally carries one or more substituents having the same meaningas R^(2′) in claim 1, and Q is as defined in claim 1, or a tautomericform thereof, or a pharmaceutically acceptable salt thereof.
 9. Acompound as claimed in claim 8, in which V is —OH, —OC₂H₅, —OCH₃, or—NHOH, or a tautomeric form thereof, or a pharmaceutically acceptablesalt thereof.
 10. A compound of general formula (B)

in which: W, X, Y and Z are each independently O, S, S(═O), S(═O)₂, NR⁴,—N═, CR⁴R⁵, or —C(R⁴)═, where R⁴ and R⁵ may be independently R^(2′), orW and X together or X and Y together form a 5 or 6 membered fused ringthat optionally includes one or more heteroatoms and that optionallycarries one or more substituents R^(2′), or Y may represent a bondlinking X and Z, the linkages between the pairs of atoms WX, XY and YZ(a) are all be single bonds, or (b) one of the linkages WX, X—Y YZ is adouble bond and the other linkages are single bonds, or (c) both WX andYZ are double bonds and XY is a single bond or (d) WX is a single ordouble bond and Y is a bond linking X and Z, Y being a single bond if WXis a double bond or a single or double bond if WX is a single bond; R⁶,R⁷ and R⁸ (each of which may have any location on the ring) mayindependently each have the same meaning as R^(2′), or two of thesubstituents R⁶, R⁷ and R⁸ may be linked to form a five-, six- orseven-membered ring that is fused to the benzene ring and that isheteroaryl, heterocycloalkenyl, cycloalkeneyl, cycloalkyl orheterocycloalkyl either unsubstituted or bearing one, two or threesubstituents that each independently has the same meaning as R^(2′), Qstands for (C₁-C₈) alkyl that optionally includes a single double bond,which may be in the position adjacent to the carbonyl group, and isoptionally interrupted by a C₆ aryl ring; (C₂-C₆) alkenyl or (C₂-C₆)alkynyl comprising one or more C═C bond or C≡C bond; R^(2′) is hydrogen,(C₁-C₆) alkyl, substituted (C₁-C₆) alkyl, or unsaturated (C₂-C₆) alkenylor alkynyl comprising one or more C═C bond or C≡C bonds, (C₆ or C₁₀)aryl or 6- or 10-membered heteroaryl, or a combination thereof to form alinked or fused ring system, (C₁-C₆) alkoxy, (C₁-C₆) thioalkoxy,hydroxyl, (C₁-C₆) hydroxyalkyl, halo, (C₁-C₆) haloalkyl, cyano, nitro,amino, amido, (C₁-C₆) alkylamino, (C₁-C₆) alkylcarbonyloxy, (C₁-C₆)alkoxycarbonyl, (C₁-C₆) alkylcarbonyl, (C₁-C₁₀) alkylthiocarbonyl,(C₁-C₆) alkylsulfonylamino, aminosulfonyl, (C₁-C₆) alkylsulfinyl, or(C₁-C₆) alkylsulfonyl; or a tautomeric form thereof, or apharmaceutically acceptable salt thereof.
 11. A compound of claim 10, inwhich, in the formula (B): W, X, Y and Z are each independently be O, S,NR⁴, —N═, CR⁴R⁵, —C(R⁴)═, where R⁴ and R⁵ may each independently havethe same meaning as R^(2′), or Y is a bond between X and Z; R⁸ standsfor H, R⁷ stands for H and R⁶ is an atom or group within the definitionof R^(2′) and having 6 atoms or fewer, or a tautomeric form thereof, ora pharmaceutically acceptable salt thereof.
 12. A compound of claim 10,in which, in the formula (B): (a) one of Z-Y and W—X is N═CR⁴ and theother is CR⁴═CR⁴; (b) Z-Y is CR⁴═N and W—X is CR⁴═CR⁴; (c) X is ═N, Y-Zis CR⁴═CR⁴ and W is CR⁴; (d) W is N and X, Y and Z is each CR⁴ andwherein the ring containing N, W, X, Y, Z is an aromatic ring; (e) W andZ is each N and X and Y is each CR⁴ and wherein the ring containing N,W, X, Y, Z is an aromatic ring; (f) Y and Z is each N and W and X iseach CR⁴ and wherein the ring containing N, W, X, Y, Z is an aromaticring; or (g) X and Y is each N and X and W is each CR⁴ and wherein thering containing N, W, X, Y, Z is an aromatic ring; where R⁴ is hydrogen,(C₁-C₆) alkyl, substituted (C₁-C₆) alkyl, or unsaturated (C₂-C₆) alkenylor alkynyl comprising one or more C═C bond or C≡C bonds, (C₆ or C₁₀)aryl or (C₆ or C₁₀) heteroaryl, or a combination thereof to form alinked or fused ring system, (C₁-C₆) alkoxy, (C₁-C₆) thioalkoxy,hydroxyl, (C₁-C₆) hydroxyalkyl, halo, (C₁-C₆) haloalkyl, cyano, nitro,amino, amido, (C₁-C₆) alkylamino, (C₁-C₆) alkylcarbonyloxy, (C₁-C₆)alkoxycarbonyl, (C₁-C₆) alkylcarbonyl, (C₁-C₁₀) alkylthiocarbonyl,(C₁-C₆) alkylsulfonylamino, aminosulfonyl, (C₁-C₆) alkylsulfinyl, or(C₁-C₆) alkylsulfonyl, or a tautomeric form thereof, or apharmaceutically acceptable salt thereof.
 13. A compound as claimed inclaim 10, in which: W, X, Y and Z is each independently O, S, S(═O),S(═O)₂, NR⁴, —N═, CR⁴R⁵, or —C(R⁴)═, where R⁴ and R⁵ are eachindependently hydrogen, (C₁-C₆) alkyl, substituted (C₁-C₆) alkyl, orunsaturated (C₂-C₆) alkenyl or alkynyl comprising one or more C═C bondor C≡C bonds, (C₆ or C₁₀) aryl or (C₆ or C₁₀) heteroaryl, or acombination thereof to form a linked or fused ring system, (C₁-C₆)alkoxy, (C₁-C₆) thioalkoxy, hydroxyl, (C₁-C₆) hydroxyalkyl, halo,(C₁-C₆) haloalkyl, cyano, nitro, amino, amido, (C₁-C₆) alkylamino,(C₁-C₆) alkylcarbonyloxy, (C₁-C₆) alkoxycarbonyl, (C₁-C₆) alkylcarbonyl,(C₁-C₁₀) alkylthio carbonyl, (C₁-C₆) alkylsulfonylamino, aminosulfonyl,(C₁-C₆) alkylsulfinyl, or (C₁-C₆) alkylsulfonyl, or W and X together orX and Y together form a 5 or 6 membered fused ring that optionallyincludes one or more heteroatoms and that optionally carries one or moresubstituents selected from hydrogen, (C₁-C₆) alkyl, substituted (C₁-C₆)alkyl, or unsaturated (C₂-C₆) alkenyl or alkynyl comprising one or moreC═C bond or C≡C bonds, (C₆ or C₁₀) aryl or (C₆ or C₁₀) heteroaryl, or acombination thereof to form a linked or fused ring system, (C₁-C₆)alkoxy, (C₁-C₆) thioalkoxy, hydroxyl, (C₁-C₆) hydroxyalkyl, halo,(C₁-C₆) haloalkyl, cyano, nitro, amino, amido, (C₁-C₆) alkylamino,(C₁-C₆) alkylcarbonyloxy, (C₁-C₆) alkoxycarbonyl, (C₁-C₆) alkylcarbonyl,(C₁-C₁₀) alkylthiocarbonyl, (C₁-C₆) alkylsulfonylamino, aminosulfonyl,(C₁-C₆) alkylsulfinyl, or (C₁-C₆) alkylsulfonyl, or a tautomeric formthereof, or a pharmaceutically acceptable salt thereof.
 14. A compoundas claimed in claim 1 which is:2-(3-Methyl-1,2,4-thiadiazol-5-yl)octanedioic acid 8-hydroxyamide1-phenylamide (A1) 2-(Pyrazin-2-yl)octanedioic acid 8-hydroxyamide1-phenylamide (B1) or 2-Phenylcarbamoyloctanedioic acid 8-hydroxyamide1-phenylamide (C1) or a tautomeric form thereof, or a pharmaceuticallyacceptable salt thereof.
 15. A process for the preparation of a compoundof claim 1 having general formula (I)

the process comprising reacting a compound of the general formula (VI)with VH:

where, in the compound of the general formulae (I) and (VI), Q, V, R¹ toR³, Y and Z are as defined in claim 1, and OR¹¹ is any groupdisplaceable by VH, where V is identical to the group V in compound (I),but not displaceable by R¹NH₂ where R¹ is identical to the group R¹ incompound (I); R¹¹ is aryl, heteroaryl or (C₁-C₆) alkyl.
 16. A process asclaimed in claim 15, wherein the compound of the general formula (VI):

is made by coupling a compound of the general formula (V)

with an amine R¹NH₂ where, in compounds of the general formulae (V) and(VI) and in the amine R¹NH₂, Q, V, R¹ to R³, Y, Z, and OR¹¹ are asdefined in claim 15, and R¹² is R³Y═CZR² where R², R³, Y and Z areidentical to the same groups in the compound of Formula (VI).
 17. Aprocess as claimed in claim 16, in which the compound of general formula(V)

is made by hydrolysing a compound of the general formula (IV)

under acidic conditions to remove the R⁹ protecting groups anddecarboxylating the resulting product by heating, with or without acid,where, in compounds of the general formulae (IV) and (V), Q, R¹¹, andR¹² are as defined in claim 16, R⁹ is a protecting group hydrolysableunder neutral or acidic conditions without the hydrolysis of R¹¹; andR¹⁰ stands for H or R³Y═CZR².
 18. A process as claimed in claim 17, inwhich the compound of general formula (IV)

is made by reacting a compound of general formula (II) with a compoundof the general formula (III)

in the presence of a base where: Q, R⁹, R¹⁰ and R¹¹ are as defined inclaim 17, and T is a leaving group.
 19. A process of claim 15, for thepreparation of a compound having general formula (A), or general formula(B)

wherein the compound of the formula VI is an ester 8, or ester 13,respectively,

and the compound VH is hydroxylamine, wherein R⁶-R⁸ (each of which mayhave any location on the ring) each independently has the same meaningas R^(2′), or two of the substituents R⁶, R⁷ and R⁸ may be linked toform a five-, six- or seven-membered ring that is fused with the benzenering and that is heteroaryl, heterocycloalkenyl, cycloalkenyl,cycloalkyl or heterocycloalkyl either unsubstituted or bearing one, twoor three substituents that each independently has the same meaning asR^(2′), in the compound having general formula (A) and ester 8, W, X andZ are independently O, S, S(═O), S(═O)₂, NR⁴, —N═, CR⁴R⁵, or —(R⁴)═,where R⁴ and R⁵ may independently have the same meaning as R^(2′) or Wand X together or X and Z together form a 5 or 6 membered fused ringthat optionally includes one or more heteroatoms and that optionallycarry one or more substituents have the same meaning as R^(2′), in thecompound having general formula (B) and ester 13, W, X, Y and Z mayindependently be O, S, S(═O), S(═O)₂, NR⁴, —N═, CR⁴R⁵, or —C(R⁴)═, whereR⁴ and R⁵ may each independently have the same meaning as R^(2′), and Ymay represent a bond linking X and Z, the linkages between the pairs ofatoms WX, XY and YZ (a) may all be single bonds, or (b) one of thelinkages W—X, X-Y and Y-Z may be double bond and the other linkages maybe single bonds, or (c) linkages WX and YZ may be double bonds andlinkage XY may be a single bond, or W and X together or X and Z togetherform a 5 or 6 membered fused ring that optionally includes one or moreheteroatoms and that optionally carries one or more substituents havingthe same meaning as R^(2′) and the bonds between W and X, and between Xand Z may be either both single bonds, or one single bond and one doublebond, and OR¹¹ is any group displaceable by hydroxylamine.
 20. A processof making an ester of the general formula 8, or general formula 13

the process comprising coupling a compound of general formula (6), orgeneral formula (12), respectively, with an amine of general formula(7):

wherein, Q stands for (C₁-C₈) alkyl that optionally includes a singledouble bond, which may be in the position adjacent to the carbonylgroup, and is optionally interrupted by a C₆ aryl ring; (C₂-C₆) alkenylor (C₂-C₆) alkenyl comprising one or more C═C bond or C≡C bond; R⁶ to R⁸(each of which may have any location on the ring) each independently hasthe same meaning as R^(2′), or two of the substituents R⁶, R⁷ and R⁸ maybe linked to form a five-, six- or seven-membered ring that is fusedwith the benzene ring and that is heteroaryl, heterocycloalkenyl,cycloalkenyl, cycloalkyl or heterocycloalkyl either unsubstituted orbearing one, two or three substituents that each independently has thesame meaning as R², in compounds of general formulae (6) and (8), W, Xand Z are independently O, S, S(═O), S(═O)₂, NR⁴, —N═, CR⁴R⁵, or—C(R⁴)═, where R⁴ and R⁵ may independently have the same meaning asR^(2′) or W and X together or X and Z together form a 5 or 6 memberedfused ring, e.g. a fused benzene ring, that optionally includes one ormore heteroatoms and that optionally carry one or more substituentshaving the same meaning as R^(2′); the bonds between W and X, andbetween X and Z may be either both single bonds, or one single bond andone double bond, in compounds of general formulae (12) and (13), W, X, Yand Z may independently be O, S, S(═O), S(═O)₂, NR⁴, —N═, CR⁴R⁵, or—C(R⁴)═, where R⁴ and R⁵ may each independently have the same meaning asR^(2′), and Y may represent a bond linking X and Z, the linkage betweenthe pairs of atoms WX, XY and YZ (a) may all be single bonds, or (b) oneof the linkages W—X, X-Y and Y-Z may be double bond and the otherlinkages may be single bonds, or (c) linkages WX and YZ may be doublebonds and linkage XY may be a single bond, or W and X together or X andZ together form a 5 or 6 membered fused ring that optionally includesone or more heteroatoms and that optionally carries one or moresubstituents having the same meaning as R^(2′); R^(2′) is hydrogen,(C₁-C₆) alkyl, substituted (C₁-C₆) alkyl, or unsaturated (C₂-C₆) alkenylor alkynyl comprising one or more C═C bond or C≡C bonds, (C₆ or C₁₀)aryl or 6- or 10-membered heteroaryl, or a combination thereof to form alinked or fused ring system, (C₁-C₆) alkoxy, (C₁-C₆) thioalkoxy,hydroxyl, (C₁-C₆) hydroxyalkyl, halo, (C₁-C₆) haloalkyl, cyano, nitro,amino, amido, (C₁-C₆) alkylamino, (C₁-C₆) alkylcarbonyloxy, (C₁-C₆)alkoxycarbonyl, (C₁-C₆) alkylcarbonyl, (C₁-C₁₀) alkylthiocarbonyl,(C₁-C₆) alkylsulfonylamino, aminosulfonyl, (C₁-C₆) alkylsulfinyl, or(C₁-C₆) alkylsulfonyl; and OR¹¹ is any group displaceable byhydroxylamine but not displaceable by the amine of general formula (7).21. A pharmaceutical composition comprising a compound of generalformula (I) of claim 1, and optionally a pharmaceutically acceptableadjuvant and/or diluent or a pharmaceutically active compound other thana compound of general formula (I) of claim
 1. 22. A method of inhibitinghistone deacetylase activity in an individual comprising administeringto the individual a therapeutically effective amount of a compound ofgeneral formula (I) of claim 1.